diff --git a/embed/extmod/modtrezorcrypto/modtrezorcrypto-bip32.h b/embed/extmod/modtrezorcrypto/modtrezorcrypto-bip32.h
index d6ba9d1beb..306f60ea6b 100644
--- a/embed/extmod/modtrezorcrypto/modtrezorcrypto-bip32.h
+++ b/embed/extmod/modtrezorcrypto/modtrezorcrypto-bip32.h
@@ -422,7 +422,16 @@ STATIC mp_obj_t mod_trezorcrypto_HDNode_ethereum_pubkeyhash(mp_obj_t self) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_HDNode_ethereum_pubkeyhash_obj, mod_trezorcrypto_HDNode_ethereum_pubkeyhash);
 
+STATIC mp_obj_t mod_trezorcrypto_HDNode___del__(mp_obj_t self) {
+    mp_obj_HDNode_t *o = MP_OBJ_TO_PTR(self);
+    o->fingerprint = 0;
+    memzero(&o->hdnode, sizeof(o->hdnode));
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_HDNode___del___obj, mod_trezorcrypto_HDNode___del__);
+
 STATIC const mp_rom_map_elem_t mod_trezorcrypto_HDNode_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&mod_trezorcrypto_HDNode___del___obj) },
     { MP_ROM_QSTR(MP_QSTR_derive), MP_ROM_PTR(&mod_trezorcrypto_HDNode_derive_obj) },
     { MP_ROM_QSTR(MP_QSTR_derive_cardano), MP_ROM_PTR(&mod_trezorcrypto_HDNode_derive_cardano_obj) },
     { MP_ROM_QSTR(MP_QSTR_derive_path), MP_ROM_PTR(&mod_trezorcrypto_HDNode_derive_path_obj) },
@@ -539,9 +548,7 @@ STATIC mp_obj_t mod_trezorcrypto_bip32_from_mnemonic_cardano(mp_obj_t mnemonic,
     return MP_OBJ_FROM_PTR(o);
 }
 
-STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_bip32_from_mnemonic_cardano_obj,
-        mod_trezorcrypto_bip32_from_mnemonic_cardano);
-
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_bip32_from_mnemonic_cardano_obj, mod_trezorcrypto_bip32_from_mnemonic_cardano);
 
 STATIC const mp_rom_map_elem_t mod_trezorcrypto_bip32_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_bip32) },
diff --git a/src/apps/cardano/__init__.py b/src/apps/cardano/__init__.py
index 022a12f197..dcfa3b5f41 100644
--- a/src/apps/cardano/__init__.py
+++ b/src/apps/cardano/__init__.py
@@ -1,6 +1,10 @@
 from trezor import wire
 from trezor.messages import MessageType
 
+from apps.common import HARDENED
+
+SEED_NAMESPACE = [[HARDENED | 44, HARDENED | 1815]]
+
 
 def boot():
     wire.add(MessageType.CardanoGetAddress, __name__, "get_address")
diff --git a/src/apps/cardano/address.py b/src/apps/cardano/address.py
index 1f8a412a08..078d309035 100644
--- a/src/apps/cardano/address.py
+++ b/src/apps/cardano/address.py
@@ -1,8 +1,27 @@
 from trezor.crypto import base58, crc, hashlib
 
-from . import cbor
+from apps.cardano import cbor
+from apps.common import HARDENED
+from apps.common.seed import remove_ed25519_prefix
 
-from apps.common import HARDENED, seed
+
+def derive_address_and_node(keychain, path: list):
+    node = keychain.derive(path)
+
+    address_payload = None
+    address_attributes = {}
+
+    address_root = _get_address_root(node, address_payload)
+    address_type = 0
+    address_data = [address_root, address_attributes, address_type]
+    address_data_encoded = cbor.encode(address_data)
+
+    address = base58.encode(
+        cbor.encode(
+            [cbor.Tagged(24, address_data_encoded), crc.crc32(address_data_encoded)]
+        )
+    )
+    return (address, node)
 
 
 def validate_full_path(path: list) -> bool:
@@ -36,31 +55,9 @@ def _address_hash(data) -> bytes:
 
 
 def _get_address_root(node, payload):
-    extpubkey = seed.remove_ed25519_prefix(node.public_key()) + node.chain_code()
+    extpubkey = remove_ed25519_prefix(node.public_key()) + node.chain_code()
     if payload:
         payload = {1: cbor.encode(payload)}
     else:
         payload = {}
     return _address_hash([0, [0, extpubkey], payload])
-
-
-def derive_address_and_node(root_node, path: list):
-    derived_node = root_node.clone()
-
-    address_payload = None
-    address_attributes = {}
-
-    for indice in path:
-        derived_node.derive_cardano(indice)
-
-    address_root = _get_address_root(derived_node, address_payload)
-    address_type = 0
-    address_data = [address_root, address_attributes, address_type]
-    address_data_encoded = cbor.encode(address_data)
-
-    address = base58.encode(
-        cbor.encode(
-            [cbor.Tagged(24, address_data_encoded), crc.crc32(address_data_encoded)]
-        )
-    )
-    return (address, derived_node)
diff --git a/src/apps/cardano/get_address.py b/src/apps/cardano/get_address.py
index 660826c801..9b03ebca47 100644
--- a/src/apps/cardano/get_address.py
+++ b/src/apps/cardano/get_address.py
@@ -1,28 +1,23 @@
 from trezor import log, ui, wire
-from trezor.crypto import bip32
 from trezor.messages.CardanoAddress import CardanoAddress
 
-from .address import derive_address_and_node, validate_full_path
-from .layout import confirm_with_pagination
-
-from apps.common import paths, seed, storage
+from apps.cardano import seed
+from apps.cardano.address import derive_address_and_node, validate_full_path
+from apps.cardano.layout import confirm_with_pagination
+from apps.common import paths
 
 
 async def get_address(ctx, msg):
+    keychain = await seed.get_keychain(ctx)
+
     await paths.validate_path(ctx, validate_full_path, path=msg.address_n)
 
-    mnemonic = storage.get_mnemonic()
-    passphrase = await seed._get_cached_passphrase(ctx)
-    root_node = bip32.from_mnemonic_cardano(mnemonic, passphrase)
-
     try:
-        address, _ = derive_address_and_node(root_node, msg.address_n)
+        address, _ = derive_address_and_node(keychain, msg.address_n)
     except ValueError as e:
         if __debug__:
             log.exception(__name__, e)
         raise wire.ProcessError("Deriving address failed")
-    mnemonic = None
-    root_node = None
 
     if msg.show_display:
         if not await confirm_with_pagination(
diff --git a/src/apps/cardano/get_public_key.py b/src/apps/cardano/get_public_key.py
index 24b7417912..8ebe9e3ef7 100644
--- a/src/apps/cardano/get_public_key.py
+++ b/src/apps/cardano/get_public_key.py
@@ -1,42 +1,38 @@
 from ubinascii import hexlify
 
 from trezor import log, wire
-from trezor.crypto import bip32
 from trezor.messages.CardanoPublicKey import CardanoPublicKey
 from trezor.messages.HDNodeType import HDNodeType
 
-from .address import derive_address_and_node
-
-from apps.common import layout, paths, seed, storage
+from apps.cardano import seed
+from apps.cardano.address import derive_address_and_node
+from apps.common import layout, paths
+from apps.common.seed import remove_ed25519_prefix
 
 
 async def get_public_key(ctx, msg):
+    keychain = await seed.get_keychain(ctx)
+
     await paths.validate_path(
         ctx, paths.validate_path_for_get_public_key, path=msg.address_n, slip44_id=1815
     )
 
-    mnemonic = storage.get_mnemonic()
-    passphrase = await seed._get_cached_passphrase(ctx)
-    root_node = bip32.from_mnemonic_cardano(mnemonic, passphrase)
-
     try:
-        key = _get_public_key(root_node, msg.address_n)
+        key = _get_public_key(keychain, msg.address_n)
     except ValueError as e:
         if __debug__:
             log.exception(__name__, e)
         raise wire.ProcessError("Deriving public key failed")
-    mnemonic = None
-    root_node = None
 
     if msg.show_display:
         await layout.show_pubkey(ctx, key.node.public_key)
     return key
 
 
-def _get_public_key(root_node, derivation_path: list):
-    _, node = derive_address_and_node(root_node, derivation_path)
+def _get_public_key(keychain, derivation_path: list):
+    _, node = derive_address_and_node(keychain, derivation_path)
 
-    public_key = hexlify(seed.remove_ed25519_prefix(node.public_key())).decode()
+    public_key = hexlify(remove_ed25519_prefix(node.public_key())).decode()
     chain_code = hexlify(node.chain_code()).decode()
     xpub_key = public_key + chain_code
 
@@ -45,7 +41,7 @@ def _get_public_key(root_node, derivation_path: list):
         child_num=node.child_num(),
         fingerprint=node.fingerprint(),
         chain_code=node.chain_code(),
-        public_key=seed.remove_ed25519_prefix(node.public_key()),
+        public_key=remove_ed25519_prefix(node.public_key()),
     )
 
     return CardanoPublicKey(node=node_type, xpub=xpub_key)
diff --git a/src/apps/cardano/seed.py b/src/apps/cardano/seed.py
new file mode 100644
index 0000000000..102c19b69b
--- /dev/null
+++ b/src/apps/cardano/seed.py
@@ -0,0 +1,43 @@
+from trezor import wire
+from trezor.crypto import bip32
+
+from apps.cardano import SEED_NAMESPACE
+from apps.common import cache, storage
+from apps.common.request_passphrase import protect_by_passphrase
+
+
+class Keychain:
+    def __init__(self, path: list, root: bip32.HDNode):
+        self.path = path
+        self.root = root
+
+    def derive(self, node_path: list) -> bip32.HDNode:
+        # check we are in the cardano namespace
+        prefix = node_path[: len(self.path)]
+        suffix = node_path[len(self.path) :]
+        if prefix != self.path:
+            raise wire.DataError("Forbidden key path")
+        # derive child node from the root
+        node = self.root.clone()
+        for i in suffix:
+            node.derive_cardano(i)
+        return node
+
+
+async def get_keychain(ctx: wire.Context) -> Keychain:
+    if not storage.is_initialized():
+        raise wire.ProcessError("Device is not initialized")
+
+    # derive the root node from mnemonic and passphrase
+    passphrase = cache.get_passphrase()
+    if passphrase is None:
+        passphrase = await protect_by_passphrase(ctx)
+        cache.set_passphrase(passphrase)
+    root = bip32.from_mnemonic_cardano(storage.get_mnemonic(), passphrase)
+
+    # derive the namespaced root node
+    for i in SEED_NAMESPACE[0]:
+        root.derive_cardano(i)
+
+    keychain = Keychain(SEED_NAMESPACE[0], root)
+    return keychain
diff --git a/src/apps/cardano/sign_tx.py b/src/apps/cardano/sign_tx.py
index 970224d586..ae453af1e9 100644
--- a/src/apps/cardano/sign_tx.py
+++ b/src/apps/cardano/sign_tx.py
@@ -1,18 +1,17 @@
 from trezor import log, ui, wire
-from trezor.crypto import base58, bip32, hashlib
+from trezor.crypto import base58, hashlib
 from trezor.crypto.curve import ed25519
 from trezor.messages.CardanoSignedTx import CardanoSignedTx
 from trezor.messages.CardanoTxRequest import CardanoTxRequest
 from trezor.messages.MessageType import CardanoTxAck
 from trezor.ui.text import BR
 
-from .address import derive_address_and_node, validate_full_path
-from .layout import confirm_with_pagination, progress
-
-from apps.cardano import cbor
-from apps.common import seed, storage
+from apps.cardano import cbor, seed
+from apps.cardano.address import derive_address_and_node, validate_full_path
+from apps.cardano.layout import confirm_with_pagination, progress
 from apps.common.layout import address_n_to_str, split_address
 from apps.common.paths import validate_path
+from apps.common.seed import remove_ed25519_prefix
 from apps.homescreen.homescreen import display_homescreen
 
 
@@ -80,9 +79,7 @@ async def request_transaction(ctx, tx_req: CardanoTxRequest, index: int):
 
 
 async def sign_tx(ctx, msg):
-    mnemonic = storage.get_mnemonic()
-    passphrase = await seed._get_cached_passphrase(ctx)
-    root_node = bip32.from_mnemonic_cardano(mnemonic, passphrase)
+    keychain = await seed.get_keychain(ctx)
 
     progress.init(msg.transactions_count, "Loading data")
 
@@ -103,7 +100,7 @@ async def sign_tx(ctx, msg):
 
         # sign the transaction bundle and prepare the result
         transaction = Transaction(
-            msg.inputs, msg.outputs, transactions, root_node, msg.network
+            msg.inputs, msg.outputs, transactions, keychain, msg.network
         )
         tx_body, tx_hash = transaction.serialise_tx()
         tx = CardanoSignedTx(tx_body=tx_body, tx_hash=tx_hash)
@@ -135,12 +132,12 @@ def _micro_ada_to_ada(amount: float) -> float:
 
 class Transaction:
     def __init__(
-        self, inputs: list, outputs: list, transactions: list, root_node, network: int
+        self, inputs: list, outputs: list, transactions: list, keychain, network: int
     ):
         self.inputs = inputs
         self.outputs = outputs
         self.transactions = transactions
-        self.root_node = root_node
+        self.keychain = keychain
         # attributes have to be always empty in current Cardano
         self.attributes = {}
         if network == 1:
@@ -170,7 +167,7 @@ class Transaction:
 
         nodes = []
         for input in self.inputs:
-            _, node = derive_address_and_node(self.root_node, input.address_n)
+            _, node = derive_address_and_node(self.keychain, input.address_n)
             nodes.append(node)
 
         for index, output_index in enumerate(output_indexes):
@@ -198,7 +195,7 @@ class Transaction:
 
         for output in self.outputs:
             if output.address_n:
-                address, _ = derive_address_and_node(self.root_node, output.address_n)
+                address, _ = derive_address_and_node(self.keychain, output.address_n)
                 change_addresses.append(address)
                 change_derivation_paths.append(output.address_n)
                 change_coins.append(output.amount)
@@ -225,7 +222,7 @@ class Transaction:
                 node.private_key(), node.private_key_ext(), message
             )
             extended_public_key = (
-                seed.remove_ed25519_prefix(node.public_key()) + node.chain_code()
+                remove_ed25519_prefix(node.public_key()) + node.chain_code()
             )
             witnesses.append(
                 [
diff --git a/src/apps/common/seed.py b/src/apps/common/seed.py
index a2a27aab02..1890b013b2 100644
--- a/src/apps/common/seed.py
+++ b/src/apps/common/seed.py
@@ -4,41 +4,75 @@ from trezor.crypto import bip32, bip39
 from apps.common import cache, storage
 from apps.common.request_passphrase import protect_by_passphrase
 
-_DEFAULT_CURVE = "secp256k1"
+allow = list
 
 
-async def derive_node(
-    ctx: wire.Context, path: list, curve_name: str = _DEFAULT_CURVE
-) -> bip32.HDNode:
-    seed = await _get_cached_seed(ctx)
-    node = bip32.from_seed(seed, curve_name)
-    node.derive_path(path)
-    return node
+class Keychain:
+    """
+    Keychain provides an API for deriving HD keys from previously allowed
+    key-spaces.
+    """
+
+    def __init__(self, seed: bytes, namespaces: list):
+        self.seed = seed
+        self.namespaces = namespaces
+        self.roots = [None] * len(namespaces)
+
+    def __del__(self):
+        for root in self.roots:
+            if root is not None:
+                root.__del__()
+        del self.roots
+        del self.seed
+
+    def derive(self, node_path: list, curve_name: str = "secp256k1") -> bip32.HDNode:
+        # find the root node index
+        root_index = 0
+        for curve, *path in self.namespaces:
+            prefix = node_path[: len(path)]
+            suffix = node_path[len(path) :]
+            if curve == curve_name and path == prefix:
+                break
+            root_index += 1
+        else:
+            raise wire.DataError("Forbidden key path")
+
+        # create the root node if not cached
+        root = self.roots[root_index]
+        if root is None:
+            root = bip32.from_seed(self.seed, curve_name)
+            root.derive_path(path)
+            self.roots[root_index] = root
+
+        # derive child node from the root
+        node = root.clone()
+        node.derive_path(suffix)
+        return node
 
 
-async def _get_cached_seed(ctx: wire.Context) -> bytes:
+async def get_keychain(ctx: wire.Context, namespaces: list) -> Keychain:
     if not storage.is_initialized():
         raise wire.ProcessError("Device is not initialized")
-    if cache.get_seed() is None:
-        passphrase = await _get_cached_passphrase(ctx)
+
+    seed = cache.get_seed()
+    if seed is None:
+        # derive seed from mnemonic and passphrase
+        passphrase = cache.get_passphrase()
+        if passphrase is None:
+            passphrase = await protect_by_passphrase(ctx)
+            cache.set_passphrase(passphrase)
         seed = bip39.seed(storage.get_mnemonic(), passphrase)
         cache.set_seed(seed)
-    return cache.get_seed()
 
-
-async def _get_cached_passphrase(ctx: wire.Context) -> str:
-    if cache.get_passphrase() is None:
-        passphrase = await protect_by_passphrase(ctx)
-        cache.set_passphrase(passphrase)
-    return cache.get_passphrase()
+    keychain = Keychain(seed, namespaces)
+    return keychain
 
 
 def derive_node_without_passphrase(
-    path: list, curve_name: str = _DEFAULT_CURVE
+    path: list, curve_name: str = "secp256k1"
 ) -> bip32.HDNode:
     if not storage.is_initialized():
         raise Exception("Device is not initialized")
-
     seed = bip39.seed(storage.get_mnemonic(), "")
     node = bip32.from_seed(seed, curve_name)
     node.derive_path(path)
diff --git a/src/apps/common/signverify.py b/src/apps/common/signverify.py
index 99476f740f..4b13731238 100644
--- a/src/apps/common/signverify.py
+++ b/src/apps/common/signverify.py
@@ -3,7 +3,7 @@ from ubinascii import hexlify
 from trezor.crypto.hashlib import blake256, sha256
 from trezor.utils import HashWriter
 
-from apps.wallet.sign_tx.signing import write_varint
+from apps.wallet.sign_tx.writers import write_varint
 
 
 def message_digest(coin, message):
diff --git a/src/apps/ethereum/__init__.py b/src/apps/ethereum/__init__.py
index f0b0ff9394..04b07a773d 100644
--- a/src/apps/ethereum/__init__.py
+++ b/src/apps/ethereum/__init__.py
@@ -1,9 +1,12 @@
 from trezor import wire
 from trezor.messages import MessageType
 
+from apps.common import HARDENED
+
 
 def boot():
-    wire.add(MessageType.EthereumGetAddress, __name__, "get_address")
-    wire.add(MessageType.EthereumSignTx, __name__, "sign_tx")
-    wire.add(MessageType.EthereumSignMessage, __name__, "sign_message")
+    ns = [["secp256k1", HARDENED | 44, HARDENED | 60]]
+    wire.add(MessageType.EthereumGetAddress, __name__, "get_address", ns)
+    wire.add(MessageType.EthereumSignTx, __name__, "sign_tx", ns)
+    wire.add(MessageType.EthereumSignMessage, __name__, "sign_message", ns)
     wire.add(MessageType.EthereumVerifyMessage, __name__, "verify_message")
diff --git a/src/apps/ethereum/get_address.py b/src/apps/ethereum/get_address.py
index e0c7e7b155..39c7bacb63 100644
--- a/src/apps/ethereum/get_address.py
+++ b/src/apps/ethereum/get_address.py
@@ -1,20 +1,17 @@
-from .address import ethereum_address_hex, validate_full_path
+from trezor.crypto.curve import secp256k1
+from trezor.crypto.hashlib import sha3_256
+from trezor.messages.EthereumAddress import EthereumAddress
 
 from apps.common import paths
 from apps.common.layout import address_n_to_str, show_address, show_qr
 from apps.ethereum import networks
+from apps.ethereum.address import ethereum_address_hex, validate_full_path
 
 
-async def get_address(ctx, msg):
-    from trezor.messages.EthereumAddress import EthereumAddress
-    from trezor.crypto.curve import secp256k1
-    from trezor.crypto.hashlib import sha3_256
-    from apps.common import seed
-
+async def get_address(ctx, msg, keychain):
     await paths.validate_path(ctx, validate_full_path, path=msg.address_n)
 
-    node = await seed.derive_node(ctx, msg.address_n)
-
+    node = keychain.derive(msg.address_n)
     seckey = node.private_key()
     public_key = secp256k1.publickey(seckey, False)  # uncompressed
     address = sha3_256(public_key[1:], keccak=True).digest()[12:]
diff --git a/src/apps/ethereum/networks.py b/src/apps/ethereum/networks.py
index f5647095f6..4b72a84225 100644
--- a/src/apps/ethereum/networks.py
+++ b/src/apps/ethereum/networks.py
@@ -82,14 +82,14 @@ NETWORKS = [
     NetworkInfo(
         chain_id=30,
         slip44=137,
-        shortcut="RSK",
+        shortcut="RBTC",
         name="RSK",
         rskip60=True,
     ),
     NetworkInfo(
         chain_id=31,
         slip44=37310,
-        shortcut="tRSK",
+        shortcut="tRBTC",
         name="RSK Testnet",
         rskip60=True,
     ),
diff --git a/src/apps/ethereum/sign_message.py b/src/apps/ethereum/sign_message.py
index c869f45076..ed6fe8dbe6 100644
--- a/src/apps/ethereum/sign_message.py
+++ b/src/apps/ethereum/sign_message.py
@@ -4,11 +4,10 @@ from trezor.messages.EthereumMessageSignature import EthereumMessageSignature
 from trezor.ui.text import Text
 from trezor.utils import HashWriter
 
-from .address import validate_full_path
-
-from apps.common import paths, seed
+from apps.common import paths
 from apps.common.confirm import require_confirm
 from apps.common.signverify import split_message
+from apps.ethereum.address import validate_full_path
 
 
 def message_digest(message):
@@ -20,12 +19,11 @@ def message_digest(message):
     return h.get_digest()
 
 
-async def sign_message(ctx, msg):
+async def sign_message(ctx, msg, keychain):
     await paths.validate_path(ctx, validate_full_path, path=msg.address_n)
     await require_confirm_sign_message(ctx, msg.message)
 
-    node = await seed.derive_node(ctx, msg.address_n)
-
+    node = keychain.derive(msg.address_n)
     signature = secp256k1.sign(
         node.private_key(),
         message_digest(msg.message),
diff --git a/src/apps/ethereum/sign_tx.py b/src/apps/ethereum/sign_tx.py
index 436f7a5c40..8f94f819c3 100644
--- a/src/apps/ethereum/sign_tx.py
+++ b/src/apps/ethereum/sign_tx.py
@@ -7,10 +7,9 @@ from trezor.messages.EthereumTxRequest import EthereumTxRequest
 from trezor.messages.MessageType import EthereumTxAck
 from trezor.utils import HashWriter
 
-from .address import validate_full_path
-
-from apps.common import paths, seed
+from apps.common import paths
 from apps.ethereum import tokens
+from apps.ethereum.address import validate_full_path
 from apps.ethereum.layout import (
     require_confirm_data,
     require_confirm_fee,
@@ -21,7 +20,7 @@ from apps.ethereum.layout import (
 MAX_CHAIN_ID = 2147483629
 
 
-async def sign_tx(ctx, msg):
+async def sign_tx(ctx, msg, keychain):
     msg = sanitize(msg)
     check(msg)
     await paths.validate_path(ctx, validate_full_path, path=msg.address_n)
@@ -91,7 +90,9 @@ async def sign_tx(ctx, msg):
         sha.extend(rlp.encode(0))
 
     digest = sha.get_digest()
-    return await send_signature(ctx, msg, digest)
+    result = sign_digest(msg, keychain, digest)
+
+    return result
 
 
 def get_total_length(msg: EthereumSignTx, data_total: int) -> int:
@@ -130,9 +131,8 @@ async def send_request_chunk(ctx, data_left: int):
     return await ctx.call(req, EthereumTxAck)
 
 
-async def send_signature(ctx, msg: EthereumSignTx, digest):
-    node = await seed.derive_node(ctx, msg.address_n)
-
+def sign_digest(msg: EthereumSignTx, keychain, digest):
+    node = keychain.derive(msg.address_n)
     signature = secp256k1.sign(
         node.private_key(), digest, False, secp256k1.CANONICAL_SIG_ETHEREUM
     )
diff --git a/src/apps/lisk/__init__.py b/src/apps/lisk/__init__.py
index acef4dd9da..f4a092cec2 100644
--- a/src/apps/lisk/__init__.py
+++ b/src/apps/lisk/__init__.py
@@ -1,10 +1,13 @@
 from trezor import wire
 from trezor.messages import MessageType
 
+from apps.common import HARDENED
+
 
 def boot():
-    wire.add(MessageType.LiskGetPublicKey, __name__, "get_public_key")
-    wire.add(MessageType.LiskGetAddress, __name__, "get_address")
-    wire.add(MessageType.LiskSignMessage, __name__, "sign_message")
+    ns = [["ed25519", HARDENED | 44, HARDENED | 134]]
+    wire.add(MessageType.LiskGetPublicKey, __name__, "get_public_key", ns)
+    wire.add(MessageType.LiskGetAddress, __name__, "get_address", ns)
+    wire.add(MessageType.LiskSignTx, __name__, "sign_tx", ns)
+    wire.add(MessageType.LiskSignMessage, __name__, "sign_message", ns)
     wire.add(MessageType.LiskVerifyMessage, __name__, "verify_message")
-    wire.add(MessageType.LiskSignTx, __name__, "sign_tx")
diff --git a/src/apps/lisk/get_address.py b/src/apps/lisk/get_address.py
index 9217420c3c..c77d0045b5 100644
--- a/src/apps/lisk/get_address.py
+++ b/src/apps/lisk/get_address.py
@@ -2,14 +2,14 @@ from trezor.messages.LiskAddress import LiskAddress
 
 from .helpers import LISK_CURVE, get_address_from_public_key, validate_full_path
 
-from apps.common import paths, seed
+from apps.common import paths
 from apps.common.layout import address_n_to_str, show_address, show_qr
 
 
-async def get_address(ctx, msg):
+async def get_address(ctx, msg, keychain):
     await paths.validate_path(ctx, validate_full_path, path=msg.address_n)
 
-    node = await seed.derive_node(ctx, msg.address_n, LISK_CURVE)
+    node = keychain.derive(msg.address_n, LISK_CURVE)
     pubkey = node.public_key()
     pubkey = pubkey[1:]  # skip ed25519 pubkey marker
     address = get_address_from_public_key(pubkey)
diff --git a/src/apps/lisk/get_public_key.py b/src/apps/lisk/get_public_key.py
index 37c613997f..93e3907cf0 100644
--- a/src/apps/lisk/get_public_key.py
+++ b/src/apps/lisk/get_public_key.py
@@ -2,13 +2,13 @@ from trezor.messages.LiskPublicKey import LiskPublicKey
 
 from .helpers import LISK_CURVE, validate_full_path
 
-from apps.common import layout, paths, seed
+from apps.common import layout, paths
 
 
-async def get_public_key(ctx, msg):
+async def get_public_key(ctx, msg, keychain):
     await paths.validate_path(ctx, validate_full_path, path=msg.address_n)
 
-    node = await seed.derive_node(ctx, msg.address_n, LISK_CURVE)
+    node = keychain.derive(msg.address_n, LISK_CURVE)
     pubkey = node.public_key()
     pubkey = pubkey[1:]  # skip ed25519 pubkey marker
 
diff --git a/src/apps/lisk/sign_message.py b/src/apps/lisk/sign_message.py
index 8ccb88b72e..9b1c99834d 100644
--- a/src/apps/lisk/sign_message.py
+++ b/src/apps/lisk/sign_message.py
@@ -6,10 +6,10 @@ from trezor.utils import HashWriter
 
 from .helpers import LISK_CURVE, validate_full_path
 
-from apps.common import paths, seed
+from apps.common import paths
 from apps.common.confirm import require_confirm
 from apps.common.signverify import split_message
-from apps.wallet.sign_tx.signing import write_varint
+from apps.wallet.sign_tx.writers import write_varint
 
 
 def message_digest(message):
@@ -22,11 +22,11 @@ def message_digest(message):
     return sha256(h.get_digest()).digest()
 
 
-async def sign_message(ctx, msg):
+async def sign_message(ctx, msg, keychain):
     await paths.validate_path(ctx, validate_full_path, path=msg.address_n)
     await require_confirm_sign_message(ctx, msg.message)
 
-    node = await seed.derive_node(ctx, msg.address_n, LISK_CURVE)
+    node = keychain.derive(msg.address_n, LISK_CURVE)
     seckey = node.private_key()
     pubkey = node.public_key()
     pubkey = pubkey[1:]  # skip ed25519 pubkey marker
diff --git a/src/apps/lisk/sign_tx.py b/src/apps/lisk/sign_tx.py
index 9466620303..0ae7c0e732 100644
--- a/src/apps/lisk/sign_tx.py
+++ b/src/apps/lisk/sign_tx.py
@@ -7,16 +7,19 @@ from trezor.messages import LiskTransactionType
 from trezor.messages.LiskSignedTx import LiskSignedTx
 from trezor.utils import HashWriter
 
-from . import layout
-from .helpers import LISK_CURVE, get_address_from_public_key, validate_full_path
-
-from apps.common import paths, seed
+from apps.common import paths
+from apps.lisk import layout
+from apps.lisk.helpers import (
+    LISK_CURVE,
+    get_address_from_public_key,
+    validate_full_path,
+)
 
 
-async def sign_tx(ctx, msg):
+async def sign_tx(ctx, msg, keychain):
     await paths.validate_path(ctx, validate_full_path, path=msg.address_n)
 
-    pubkey, seckey = await _get_keys(ctx, msg)
+    pubkey, seckey = _get_keys(keychain, msg)
     transaction = _update_raw_tx(msg.transaction, pubkey)
 
     try:
@@ -37,8 +40,8 @@ async def sign_tx(ctx, msg):
     return LiskSignedTx(signature=signature)
 
 
-async def _get_keys(ctx, msg):
-    node = await seed.derive_node(ctx, msg.address_n, LISK_CURVE)
+def _get_keys(keychain, msg):
+    node = keychain.derive(msg.address_n, LISK_CURVE)
 
     seckey = node.private_key()
     pubkey = node.public_key()
diff --git a/src/apps/monero/__init__.py b/src/apps/monero/__init__.py
index c2a8364cd3..d453140650 100644
--- a/src/apps/monero/__init__.py
+++ b/src/apps/monero/__init__.py
@@ -1,12 +1,20 @@
 from trezor import wire
 from trezor.messages import MessageType
 
+from apps.common import HARDENED
+
 
 def boot():
-    wire.add(MessageType.MoneroGetAddress, __name__, "get_address")
-    wire.add(MessageType.MoneroGetWatchKey, __name__, "get_watch_only")
-    wire.add(MessageType.MoneroTransactionInitRequest, __name__, "sign_tx")
-    wire.add(MessageType.MoneroKeyImageExportInitRequest, __name__, "key_image_sync")
+    ns = [
+        ["secp256k1", HARDENED | 44, HARDENED | 128],
+        ["ed25519", HARDENED | 44, HARDENED | 128],
+    ]
+    wire.add(MessageType.MoneroGetAddress, __name__, "get_address", ns)
+    wire.add(MessageType.MoneroGetWatchKey, __name__, "get_watch_only", ns)
+    wire.add(MessageType.MoneroTransactionInitRequest, __name__, "sign_tx", ns)
+    wire.add(
+        MessageType.MoneroKeyImageExportInitRequest, __name__, "key_image_sync", ns
+    )
 
     if __debug__ and hasattr(MessageType, "DebugMoneroDiagRequest"):
         wire.add(MessageType.DebugMoneroDiagRequest, __name__, "diag")
diff --git a/src/apps/monero/get_address.py b/src/apps/monero/get_address.py
index 873420d3ca..aced5b7dc4 100644
--- a/src/apps/monero/get_address.py
+++ b/src/apps/monero/get_address.py
@@ -5,10 +5,10 @@ from apps.common.layout import address_n_to_str, show_address, show_qr
 from apps.monero import misc
 
 
-async def get_address(ctx, msg):
+async def get_address(ctx, msg, keychain):
     await paths.validate_path(ctx, misc.validate_full_path, path=msg.address_n)
 
-    creds = await misc.get_creds(ctx, msg.address_n, msg.network_type)
+    creds = misc.get_creds(keychain, msg.address_n, msg.network_type)
 
     if msg.show_display:
         desc = address_n_to_str(msg.address_n)
diff --git a/src/apps/monero/get_watch_only.py b/src/apps/monero/get_watch_only.py
index 311a6fc8bd..8a636a0a86 100644
--- a/src/apps/monero/get_watch_only.py
+++ b/src/apps/monero/get_watch_only.py
@@ -7,12 +7,12 @@ from apps.monero.layout import confirms
 from apps.monero.xmr import crypto
 
 
-async def get_watch_only(ctx, msg: MoneroGetWatchKey):
+async def get_watch_only(ctx, msg: MoneroGetWatchKey, keychain):
     await paths.validate_path(ctx, misc.validate_full_path, path=msg.address_n)
 
     await confirms.require_confirm_watchkey(ctx)
 
-    creds = await misc.get_creds(ctx, msg.address_n, msg.network_type)
+    creds = misc.get_creds(keychain, msg.address_n, msg.network_type)
     address = creds.address
     watch_key = crypto.encodeint(creds.view_key_private)
 
diff --git a/src/apps/monero/key_image_sync.py b/src/apps/monero/key_image_sync.py
index de265b8eaf..e025642310 100644
--- a/src/apps/monero/key_image_sync.py
+++ b/src/apps/monero/key_image_sync.py
@@ -14,10 +14,10 @@ from apps.monero.xmr import crypto, key_image, monero
 from apps.monero.xmr.crypto import chacha_poly
 
 
-async def key_image_sync(ctx, msg):
+async def key_image_sync(ctx, msg, keychain):
     state = KeyImageSync()
 
-    res = await _init_step(state, ctx, msg)
+    res = await _init_step(state, ctx, msg, keychain)
     while True:
         msg = await ctx.call(
             res,
@@ -46,10 +46,10 @@ class KeyImageSync:
         self.hasher = crypto.get_keccak()
 
 
-async def _init_step(s, ctx, msg):
+async def _init_step(s, ctx, msg, keychain):
     await paths.validate_path(ctx, misc.validate_full_path, path=msg.address_n)
 
-    s.creds = await misc.get_creds(ctx, msg.address_n, msg.network_type)
+    s.creds = misc.get_creds(keychain, msg.address_n, msg.network_type)
 
     await confirms.require_confirm_keyimage_sync(ctx)
 
diff --git a/src/apps/monero/misc.py b/src/apps/monero/misc.py
index 5cdd459c96..2e5cd0474a 100644
--- a/src/apps/monero/misc.py
+++ b/src/apps/monero/misc.py
@@ -1,8 +1,7 @@
 from apps.common import HARDENED
 
 
-async def get_creds(ctx, address_n=None, network_type=None):
-    from apps.common import seed
+def get_creds(keychain, address_n=None, network_type=None):
     from apps.monero.xmr import crypto, monero
     from apps.monero.xmr.credentials import AccountCreds
 
@@ -12,7 +11,7 @@ async def get_creds(ctx, address_n=None, network_type=None):
         curve = "ed25519"
     else:
         curve = "secp256k1"
-    node = await seed.derive_node(ctx, address_n, curve)
+    node = keychain.derive(address_n, curve)
 
     if use_slip0010:
         key_seed = node.private_key()
diff --git a/src/apps/monero/sign_tx.py b/src/apps/monero/sign_tx.py
index c85118681e..0382d28ac4 100644
--- a/src/apps/monero/sign_tx.py
+++ b/src/apps/monero/sign_tx.py
@@ -6,7 +6,7 @@ from trezor.messages import MessageType
 from apps.monero.signing.state import State
 
 
-async def sign_tx(ctx, received_msg):
+async def sign_tx(ctx, received_msg, keychain):
     state = State(ctx)
     mods = utils.unimport_begin()
 
@@ -18,7 +18,7 @@ async def sign_tx(ctx, received_msg):
         gc.collect()
         gc.threshold(gc.mem_free() // 4 + gc.mem_alloc())
 
-        result_msg, accept_msgs = await sign_tx_dispatch(state, received_msg)
+        result_msg, accept_msgs = await sign_tx_dispatch(state, received_msg, keychain)
         if accept_msgs is None:
             break
 
@@ -32,13 +32,13 @@ async def sign_tx(ctx, received_msg):
     return result_msg
 
 
-async def sign_tx_dispatch(state, msg):
+async def sign_tx_dispatch(state, msg, keychain):
     if msg.MESSAGE_WIRE_TYPE == MessageType.MoneroTransactionInitRequest:
         from apps.monero.signing import step_01_init_transaction
 
         return (
             await step_01_init_transaction.init_transaction(
-                state, msg.address_n, msg.network_type, msg.tsx_data
+                state, msg.address_n, msg.network_type, msg.tsx_data, keychain
             ),
             (MessageType.MoneroTransactionSetInputRequest,),
         )
diff --git a/src/apps/monero/signing/step_01_init_transaction.py b/src/apps/monero/signing/step_01_init_transaction.py
index df7496c1e2..a5c25ea86e 100644
--- a/src/apps/monero/signing/step_01_init_transaction.py
+++ b/src/apps/monero/signing/step_01_init_transaction.py
@@ -16,14 +16,18 @@ if False:
 
 
 async def init_transaction(
-    state: State, address_n: list, network_type: int, tsx_data: MoneroTransactionData
+    state: State,
+    address_n: list,
+    network_type: int,
+    tsx_data: MoneroTransactionData,
+    keychain,
 ):
     from apps.monero.signing import offloading_keys
     from apps.common import paths
 
     await paths.validate_path(state.ctx, misc.validate_full_path, path=address_n)
 
-    state.creds = await misc.get_creds(state.ctx, address_n, network_type)
+    state.creds = misc.get_creds(keychain, address_n, network_type)
     state.fee = state.fee if state.fee > 0 else 0
     state.tx_priv = crypto.random_scalar()
     state.tx_pub = crypto.scalarmult_base(state.tx_priv)
diff --git a/src/apps/nem/__init__.py b/src/apps/nem/__init__.py
index f75b6ff3d6..8433f24482 100644
--- a/src/apps/nem/__init__.py
+++ b/src/apps/nem/__init__.py
@@ -1,7 +1,13 @@
 from trezor import wire
 from trezor.messages import MessageType
 
+from apps.common import HARDENED
+
 
 def boot():
-    wire.add(MessageType.NEMGetAddress, __name__, "get_address")
-    wire.add(MessageType.NEMSignTx, __name__, "sign_tx")
+    ns = [
+        ["ed25519-keccak", HARDENED | 44, HARDENED | 43],
+        ["ed25519-keccak", HARDENED | 44, HARDENED | 1],
+    ]
+    wire.add(MessageType.NEMGetAddress, __name__, "get_address", ns)
+    wire.add(MessageType.NEMSignTx, __name__, "sign_tx", ns)
diff --git a/src/apps/nem/get_address.py b/src/apps/nem/get_address.py
index 2ca653e552..676e43657e 100644
--- a/src/apps/nem/get_address.py
+++ b/src/apps/nem/get_address.py
@@ -3,16 +3,15 @@ from trezor.messages.NEMAddress import NEMAddress
 from .helpers import NEM_CURVE, check_path, get_network_str
 from .validators import validate_network
 
-from apps.common import seed
 from apps.common.layout import address_n_to_str, show_address, show_qr
 from apps.common.paths import validate_path
 
 
-async def get_address(ctx, msg):
+async def get_address(ctx, msg, keychain):
     network = validate_network(msg.network)
-    await validate_path(ctx, check_path, path=msg.address_n, network=msg.network)
+    await validate_path(ctx, check_path, path=msg.address_n, network=network)
 
-    node = await seed.derive_node(ctx, msg.address_n, NEM_CURVE)
+    node = keychain.derive(msg.address_n, NEM_CURVE)
     address = node.nem_address(network)
 
     if msg.show_display:
diff --git a/src/apps/nem/sign_tx.py b/src/apps/nem/sign_tx.py
index 7ca411f8bb..1a76f163b7 100644
--- a/src/apps/nem/sign_tx.py
+++ b/src/apps/nem/sign_tx.py
@@ -2,21 +2,21 @@ from trezor.crypto.curve import ed25519
 from trezor.messages.NEMSignedTx import NEMSignedTx
 from trezor.messages.NEMSignTx import NEMSignTx
 
-from . import mosaic, multisig, namespace, transfer
-from .helpers import NEM_CURVE, NEM_HASH_ALG, check_path
-from .validators import validate
-
 from apps.common import seed
 from apps.common.paths import validate_path
+from apps.nem import mosaic, multisig, namespace, transfer
+from apps.nem.helpers import NEM_CURVE, NEM_HASH_ALG, check_path
+from apps.nem.validators import validate
 
 
-async def sign_tx(ctx, msg: NEMSignTx):
+async def sign_tx(ctx, msg: NEMSignTx, keychain):
     validate(msg)
+
     await validate_path(
         ctx, check_path, path=msg.transaction.address_n, network=msg.transaction.network
     )
 
-    node = await seed.derive_node(ctx, msg.transaction.address_n, NEM_CURVE)
+    node = keychain.derive(msg.transaction.address_n, NEM_CURVE)
 
     if msg.multisig:
         public_key = msg.multisig.signer
diff --git a/src/apps/ripple/__init__.py b/src/apps/ripple/__init__.py
index f4a863edb6..2e24cf5816 100644
--- a/src/apps/ripple/__init__.py
+++ b/src/apps/ripple/__init__.py
@@ -1,7 +1,10 @@
 from trezor import wire
 from trezor.messages import MessageType
 
+from apps.common import HARDENED
+
 
 def boot():
-    wire.add(MessageType.RippleGetAddress, __name__, "get_address")
-    wire.add(MessageType.RippleSignTx, __name__, "sign_tx")
+    ns = [["secp256k1", HARDENED | 44, HARDENED | 144]]
+    wire.add(MessageType.RippleGetAddress, __name__, "get_address", ns)
+    wire.add(MessageType.RippleSignTx, __name__, "sign_tx", ns)
diff --git a/src/apps/ripple/get_address.py b/src/apps/ripple/get_address.py
index 5af586a747..a5b26ba762 100644
--- a/src/apps/ripple/get_address.py
+++ b/src/apps/ripple/get_address.py
@@ -1,16 +1,15 @@
 from trezor.messages.RippleAddress import RippleAddress
 from trezor.messages.RippleGetAddress import RippleGetAddress
 
-from . import helpers
-
-from apps.common import paths, seed
+from apps.common import paths
 from apps.common.layout import address_n_to_str, show_address, show_qr
+from apps.ripple import helpers
 
 
-async def get_address(ctx, msg: RippleGetAddress):
+async def get_address(ctx, msg: RippleGetAddress, keychain):
     await paths.validate_path(ctx, helpers.validate_full_path, path=msg.address_n)
 
-    node = await seed.derive_node(ctx, msg.address_n)
+    node = keychain.derive(msg.address_n)
     pubkey = node.public_key()
     address = helpers.address_from_public_key(pubkey)
 
diff --git a/src/apps/ripple/sign_tx.py b/src/apps/ripple/sign_tx.py
index b35227f78d..b3d0be7c6a 100644
--- a/src/apps/ripple/sign_tx.py
+++ b/src/apps/ripple/sign_tx.py
@@ -5,17 +5,17 @@ from trezor.messages.RippleSignedTx import RippleSignedTx
 from trezor.messages.RippleSignTx import RippleSignTx
 from trezor.wire import ProcessError
 
-from . import helpers, layout
-from .serialize import serialize
-
-from apps.common import paths, seed
+from apps.common import paths
+from apps.ripple import helpers, layout
+from apps.ripple.serialize import serialize
 
 
-async def sign_tx(ctx, msg: RippleSignTx):
+async def sign_tx(ctx, msg: RippleSignTx, keychain):
     validate(msg)
+
     await paths.validate_path(ctx, helpers.validate_full_path, path=msg.address_n)
 
-    node = await seed.derive_node(ctx, msg.address_n)
+    node = keychain.derive(msg.address_n)
     source_address = helpers.address_from_public_key(node.public_key())
 
     set_canonical_flag(msg)
diff --git a/src/apps/stellar/__init__.py b/src/apps/stellar/__init__.py
index 92fba60b08..ae5e40c88a 100644
--- a/src/apps/stellar/__init__.py
+++ b/src/apps/stellar/__init__.py
@@ -1,7 +1,10 @@
 from trezor import wire
 from trezor.messages import MessageType
 
+from apps.common import HARDENED
+
 
 def boot():
-    wire.add(MessageType.StellarGetAddress, __name__, "get_address")
-    wire.add(MessageType.StellarSignTx, __name__, "sign_tx")
+    ns = [["ed25519", HARDENED | 44, HARDENED | 148]]
+    wire.add(MessageType.StellarGetAddress, __name__, "get_address", ns)
+    wire.add(MessageType.StellarSignTx, __name__, "sign_tx", ns)
diff --git a/src/apps/stellar/get_address.py b/src/apps/stellar/get_address.py
index 1e15f6b586..8b87d34f8b 100644
--- a/src/apps/stellar/get_address.py
+++ b/src/apps/stellar/get_address.py
@@ -6,10 +6,10 @@ from apps.common.layout import address_n_to_str, show_address, show_qr
 from apps.stellar import helpers
 
 
-async def get_address(ctx, msg: StellarGetAddress):
+async def get_address(ctx, msg: StellarGetAddress, keychain):
     await paths.validate_path(ctx, helpers.validate_full_path, path=msg.address_n)
 
-    node = await seed.derive_node(ctx, msg.address_n, helpers.STELLAR_CURVE)
+    node = keychain.derive(msg.address_n, helpers.STELLAR_CURVE)
     pubkey = seed.remove_ed25519_prefix(node.public_key())
     address = helpers.address_from_public_key(pubkey)
 
diff --git a/src/apps/stellar/sign_tx.py b/src/apps/stellar/sign_tx.py
index f6efa56d70..55152348b6 100644
--- a/src/apps/stellar/sign_tx.py
+++ b/src/apps/stellar/sign_tx.py
@@ -12,15 +12,15 @@ from apps.stellar import consts, helpers, layout, writers
 from apps.stellar.operations import process_operation
 
 
-async def sign_tx(ctx, msg: StellarSignTx):
-    if msg.num_operations == 0:
-        raise ProcessError("Stellar: At least one operation is required")
-
+async def sign_tx(ctx, msg: StellarSignTx, keychain):
     await paths.validate_path(ctx, helpers.validate_full_path, path=msg.address_n)
 
-    node = await seed.derive_node(ctx, msg.address_n, consts.STELLAR_CURVE)
+    node = keychain.derive(msg.address_n, consts.STELLAR_CURVE)
     pubkey = seed.remove_ed25519_prefix(node.public_key())
 
+    if msg.num_operations == 0:
+        raise ProcessError("Stellar: At least one operation is required")
+
     w = bytearray()
     await _init(ctx, w, pubkey, msg)
     _timebounds(w, msg.timebounds_start, msg.timebounds_end)
diff --git a/src/apps/tezos/__init__.py b/src/apps/tezos/__init__.py
index ba29093bd4..1c5aa3699d 100644
--- a/src/apps/tezos/__init__.py
+++ b/src/apps/tezos/__init__.py
@@ -1,8 +1,11 @@
 from trezor import wire
 from trezor.messages import MessageType
 
+from apps.common import HARDENED
+
 
 def boot():
-    wire.add(MessageType.TezosGetAddress, __name__, "get_address")
-    wire.add(MessageType.TezosSignTx, __name__, "sign_tx")
-    wire.add(MessageType.TezosGetPublicKey, __name__, "get_public_key")
+    ns = [["ed25519", HARDENED | 44, HARDENED | 1729]]
+    wire.add(MessageType.TezosGetAddress, __name__, "get_address", ns)
+    wire.add(MessageType.TezosSignTx, __name__, "sign_tx", ns)
+    wire.add(MessageType.TezosGetPublicKey, __name__, "get_public_key", ns)
diff --git a/src/apps/tezos/get_address.py b/src/apps/tezos/get_address.py
index 9640d2c971..4ff5635129 100644
--- a/src/apps/tezos/get_address.py
+++ b/src/apps/tezos/get_address.py
@@ -6,9 +6,10 @@ from apps.common.layout import address_n_to_str, show_address, show_qr
 from apps.tezos import helpers
 
 
-async def get_address(ctx, msg):
+async def get_address(ctx, msg, keychain):
     await paths.validate_path(ctx, helpers.validate_full_path, path=msg.address_n)
-    node = await seed.derive_node(ctx, msg.address_n, helpers.TEZOS_CURVE)
+
+    node = keychain.derive(msg.address_n, helpers.TEZOS_CURVE)
 
     pk = seed.remove_ed25519_prefix(node.public_key())
     pkh = hashlib.blake2b(pk, outlen=20).digest()
diff --git a/src/apps/tezos/get_public_key.py b/src/apps/tezos/get_public_key.py
index c96d468dde..c3f75ad97b 100644
--- a/src/apps/tezos/get_public_key.py
+++ b/src/apps/tezos/get_public_key.py
@@ -9,10 +9,10 @@ from apps.common.confirm import require_confirm
 from apps.tezos import helpers
 
 
-async def get_public_key(ctx, msg):
+async def get_public_key(ctx, msg, keychain):
     await paths.validate_path(ctx, helpers.validate_full_path, path=msg.address_n)
-    node = await seed.derive_node(ctx, msg.address_n, helpers.TEZOS_CURVE)
 
+    node = keychain.derive(msg.address_n, helpers.TEZOS_CURVE)
     pk = seed.remove_ed25519_prefix(node.public_key())
     pk_prefixed = helpers.base58_encode_check(pk, prefix=helpers.TEZOS_PUBLICKEY_PREFIX)
 
diff --git a/src/apps/tezos/sign_tx.py b/src/apps/tezos/sign_tx.py
index 059acefe6a..5cf0e11d3b 100644
--- a/src/apps/tezos/sign_tx.py
+++ b/src/apps/tezos/sign_tx.py
@@ -4,14 +4,15 @@ from trezor.crypto.curve import ed25519
 from trezor.messages import TezosContractType
 from trezor.messages.TezosSignedTx import TezosSignedTx
 
-from apps.common import paths, seed
+from apps.common import paths
 from apps.common.writers import write_bytes, write_uint8
 from apps.tezos import helpers, layout
 
 
-async def sign_tx(ctx, msg):
+async def sign_tx(ctx, msg, keychain):
     await paths.validate_path(ctx, helpers.validate_full_path, path=msg.address_n)
-    node = await seed.derive_node(ctx, msg.address_n, helpers.TEZOS_CURVE)
+
+    node = keychain.derive(msg.address_n, helpers.TEZOS_CURVE)
 
     if msg.transaction is not None:
         to = _get_address_from_contract(msg.transaction.destination)
diff --git a/src/apps/wallet/__init__.py b/src/apps/wallet/__init__.py
index 7fbf9b3976..fc70179cc1 100644
--- a/src/apps/wallet/__init__.py
+++ b/src/apps/wallet/__init__.py
@@ -3,12 +3,22 @@ from trezor.messages import MessageType
 
 
 def boot():
-    wire.add(MessageType.GetPublicKey, __name__, "get_public_key")
-    wire.add(MessageType.GetAddress, __name__, "get_address")
+    ns = [
+        ["curve25519"],
+        ["ed25519"],
+        ["ed25519-keccak"],
+        ["nist256p1"],
+        ["secp256k1"],
+        ["secp256k1-decred"],
+        ["secp256k1-groestl"],
+        ["secp256k1-smart"],
+    ]
+    wire.add(MessageType.GetPublicKey, __name__, "get_public_key", ns)
+    wire.add(MessageType.GetAddress, __name__, "get_address", ns)
     wire.add(MessageType.GetEntropy, __name__, "get_entropy")
-    wire.add(MessageType.SignTx, __name__, "sign_tx")
-    wire.add(MessageType.SignMessage, __name__, "sign_message")
+    wire.add(MessageType.SignTx, __name__, "sign_tx", ns)
+    wire.add(MessageType.SignMessage, __name__, "sign_message", ns)
     wire.add(MessageType.VerifyMessage, __name__, "verify_message")
-    wire.add(MessageType.SignIdentity, __name__, "sign_identity")
-    wire.add(MessageType.GetECDHSessionKey, __name__, "get_ecdh_session_key")
-    wire.add(MessageType.CipherKeyValue, __name__, "cipher_key_value")
+    wire.add(MessageType.SignIdentity, __name__, "sign_identity", ns)
+    wire.add(MessageType.GetECDHSessionKey, __name__, "get_ecdh_session_key", ns)
+    wire.add(MessageType.CipherKeyValue, __name__, "cipher_key_value", ns)
diff --git a/src/apps/wallet/cipher_key_value.py b/src/apps/wallet/cipher_key_value.py
index 44c04ad84e..b6c14663bf 100644
--- a/src/apps/wallet/cipher_key_value.py
+++ b/src/apps/wallet/cipher_key_value.py
@@ -4,11 +4,10 @@ from trezor.crypto.hashlib import sha512
 from trezor.messages.CipheredKeyValue import CipheredKeyValue
 from trezor.ui.text import Text
 
-from apps.common import seed
 from apps.common.confirm import require_confirm
 
 
-async def cipher_key_value(ctx, msg):
+async def cipher_key_value(ctx, msg, keychain):
     if len(msg.value) % 16 > 0:
         raise wire.DataError("Value length must be a multiple of 16")
 
@@ -23,7 +22,7 @@ async def cipher_key_value(ctx, msg):
         text.normal(msg.key)
         await require_confirm(ctx, text)
 
-    node = await seed.derive_node(ctx, msg.address_n)
+    node = keychain.derive(msg.address_n)
     value = compute_cipher_key_value(msg, node.private_key())
     return CipheredKeyValue(value=value)
 
diff --git a/src/apps/wallet/get_address.py b/src/apps/wallet/get_address.py
index 929aaf9d07..80096d37c5 100644
--- a/src/apps/wallet/get_address.py
+++ b/src/apps/wallet/get_address.py
@@ -1,13 +1,13 @@
 from trezor.messages import InputScriptType
 from trezor.messages.Address import Address
 
-from apps.common import coins, seed
+from apps.common import coins
 from apps.common.layout import address_n_to_str, show_address, show_qr
 from apps.common.paths import validate_path
 from apps.wallet.sign_tx import addresses
 
 
-async def get_address(ctx, msg):
+async def get_address(ctx, msg, keychain):
     coin_name = msg.coin_name or "Bitcoin"
     coin = coins.by_name(coin_name)
 
@@ -19,7 +19,7 @@ async def get_address(ctx, msg):
         script_type=msg.script_type,
     )
 
-    node = await seed.derive_node(ctx, msg.address_n, curve_name=coin.curve_name)
+    node = keychain.derive(msg.address_n, coin.curve_name)
     address = addresses.get_address(msg.script_type, coin, node, msg.multisig)
     address_short = addresses.address_short(coin, address)
 
diff --git a/src/apps/wallet/get_ecdh_session_key.py b/src/apps/wallet/get_ecdh_session_key.py
index 0d15005132..22b5b6071c 100644
--- a/src/apps/wallet/get_ecdh_session_key.py
+++ b/src/apps/wallet/get_ecdh_session_key.py
@@ -5,7 +5,7 @@ from trezor.messages.ECDHSessionKey import ECDHSessionKey
 from trezor.ui.text import Text
 from trezor.utils import chunks
 
-from apps.common import HARDENED, seed
+from apps.common import HARDENED
 from apps.common.confirm import require_confirm
 from apps.wallet.sign_identity import (
     serialize_identity,
@@ -13,7 +13,7 @@ from apps.wallet.sign_identity import (
 )
 
 
-async def get_ecdh_session_key(ctx, msg):
+async def get_ecdh_session_key(ctx, msg, keychain):
     if msg.ecdsa_curve_name is None:
         msg.ecdsa_curve_name = "secp256k1"
 
@@ -22,7 +22,7 @@ async def get_ecdh_session_key(ctx, msg):
     await require_confirm_ecdh_session_key(ctx, msg.identity)
 
     address_n = get_ecdh_path(identity, msg.identity.index or 0)
-    node = await seed.derive_node(ctx, address_n, msg.ecdsa_curve_name)
+    node = keychain.derive(address_n, msg.ecdsa_curve_name)
 
     session_key = ecdh(
         seckey=node.private_key(),
diff --git a/src/apps/wallet/get_entropy.py b/src/apps/wallet/get_entropy.py
index f953235863..e35878b07a 100644
--- a/src/apps/wallet/get_entropy.py
+++ b/src/apps/wallet/get_entropy.py
@@ -7,7 +7,6 @@ from apps.common.confirm import require_confirm
 
 
 async def get_entropy(ctx, msg):
-
     text = Text("Confirm entropy")
     text.bold("Do you really want", "to send entropy?")
     text.normal("Continue only if you", "know what you are doing!")
diff --git a/src/apps/wallet/get_public_key.py b/src/apps/wallet/get_public_key.py
index e809573441..e779ff02dc 100644
--- a/src/apps/wallet/get_public_key.py
+++ b/src/apps/wallet/get_public_key.py
@@ -3,18 +3,16 @@ from trezor.messages import InputScriptType
 from trezor.messages.HDNodeType import HDNodeType
 from trezor.messages.PublicKey import PublicKey
 
-from apps.common import coins, layout, seed
+from apps.common import coins, layout
 
 
-async def get_public_key(ctx, msg):
+async def get_public_key(ctx, msg, keychain):
     coin_name = msg.coin_name or "Bitcoin"
     coin = coins.by_name(coin_name)
+    curve_name = msg.ecdsa_curve_name or coin.curve_name
     script_type = msg.script_type or InputScriptType.SPENDADDRESS
 
-    curve_name = msg.ecdsa_curve_name
-    if not curve_name:
-        curve_name = coin.curve_name
-    node = await seed.derive_node(ctx, msg.address_n, curve_name=curve_name)
+    node = keychain.derive(msg.address_n, curve_name=curve_name)
 
     if (
         script_type in [InputScriptType.SPENDADDRESS, InputScriptType.SPENDMULTISIG]
diff --git a/src/apps/wallet/sign_identity.py b/src/apps/wallet/sign_identity.py
index 98f2136ceb..6c71390d6b 100644
--- a/src/apps/wallet/sign_identity.py
+++ b/src/apps/wallet/sign_identity.py
@@ -6,11 +6,11 @@ from trezor.messages.SignedIdentity import SignedIdentity
 from trezor.ui.text import Text
 from trezor.utils import chunks
 
-from apps.common import HARDENED, coins, seed
+from apps.common import HARDENED, coins
 from apps.common.confirm import require_confirm
 
 
-async def sign_identity(ctx, msg):
+async def sign_identity(ctx, msg, keychain):
     if msg.ecdsa_curve_name is None:
         msg.ecdsa_curve_name = "secp256k1"
 
@@ -19,7 +19,7 @@ async def sign_identity(ctx, msg):
     await require_confirm_sign_identity(ctx, msg.identity, msg.challenge_visual)
 
     address_n = get_identity_path(identity, msg.identity.index or 0)
-    node = await seed.derive_node(ctx, address_n, msg.ecdsa_curve_name)
+    node = keychain.derive(address_n, msg.ecdsa_curve_name)
 
     coin = coins.by_name("Bitcoin")
     if msg.ecdsa_curve_name == "secp256k1":
diff --git a/src/apps/wallet/sign_message.py b/src/apps/wallet/sign_message.py
index 246307476b..ab9e58f879 100644
--- a/src/apps/wallet/sign_message.py
+++ b/src/apps/wallet/sign_message.py
@@ -4,14 +4,14 @@ from trezor.messages.InputScriptType import SPENDADDRESS, SPENDP2SHWITNESS, SPEN
 from trezor.messages.MessageSignature import MessageSignature
 from trezor.ui.text import Text
 
-from apps.common import coins, seed
+from apps.common import coins
 from apps.common.confirm import require_confirm
 from apps.common.paths import validate_path
 from apps.common.signverify import message_digest, split_message
 from apps.wallet.sign_tx.addresses import get_address, validate_full_path
 
 
-async def sign_message(ctx, msg):
+async def sign_message(ctx, msg, keychain):
     message = msg.message
     address_n = msg.address_n
     coin_name = msg.coin_name or "Bitcoin"
@@ -19,7 +19,6 @@ async def sign_message(ctx, msg):
     coin = coins.by_name(coin_name)
 
     await require_confirm_sign_message(ctx, message)
-
     await validate_path(
         ctx,
         validate_full_path,
@@ -29,7 +28,7 @@ async def sign_message(ctx, msg):
         validate_script_type=False,
     )
 
-    node = await seed.derive_node(ctx, address_n, curve_name=coin.curve_name)
+    node = keychain.derive(address_n, coin.curve_name)
     seckey = node.private_key()
 
     address = get_address(script_type, coin, node)
diff --git a/src/apps/wallet/sign_tx/__init__.py b/src/apps/wallet/sign_tx/__init__.py
index a32c2b8126..6bcc1aeebd 100644
--- a/src/apps/wallet/sign_tx/__init__.py
+++ b/src/apps/wallet/sign_tx/__init__.py
@@ -3,53 +3,51 @@ from trezor.messages.MessageType import TxAck
 from trezor.messages.RequestType import TXFINISHED
 from trezor.messages.TxRequest import TxRequest
 
-from apps.common import coins, paths, seed
-from apps.wallet.sign_tx.helpers import (
-    UiConfirmFeeOverThreshold,
-    UiConfirmForeignAddress,
-    UiConfirmOutput,
-    UiConfirmTotal,
+from apps.common import paths
+from apps.wallet.sign_tx import (
+    addresses,
+    helpers,
+    layout,
+    multisig,
+    progress,
+    scripts,
+    segwit_bip143,
+    signing,
 )
 
 
 @ui.layout
-async def sign_tx(ctx, msg):
-    from apps.wallet.sign_tx import layout, progress, signing
+async def sign_tx(ctx, msg, keychain):
+    signer = signing.sign_tx(msg, keychain)
 
-    coin_name = msg.coin_name or "Bitcoin"
-    coin = coins.by_name(coin_name)
-    # TODO: rework this so we don't have to pass root to signing.sign_tx
-    root = await seed.derive_node(ctx, [], curve_name=coin.curve_name)
-
-    signer = signing.sign_tx(msg, root)
     res = None
     while True:
         try:
             req = signer.send(res)
         except signing.SigningError as e:
             raise wire.Error(*e.args)
-        except signing.MultisigError as e:
+        except multisig.MultisigError as e:
             raise wire.Error(*e.args)
-        except signing.AddressError as e:
+        except addresses.AddressError as e:
             raise wire.Error(*e.args)
-        except signing.ScriptsError as e:
+        except scripts.ScriptsError as e:
             raise wire.Error(*e.args)
-        except signing.Bip143Error as e:
+        except segwit_bip143.Bip143Error as e:
             raise wire.Error(*e.args)
         if isinstance(req, TxRequest):
             if req.request_type == TXFINISHED:
                 break
             res = await ctx.call(req, TxAck)
-        elif isinstance(req, UiConfirmOutput):
+        elif isinstance(req, helpers.UiConfirmOutput):
             res = await layout.confirm_output(ctx, req.output, req.coin)
             progress.report_init()
-        elif isinstance(req, UiConfirmTotal):
+        elif isinstance(req, helpers.UiConfirmTotal):
             res = await layout.confirm_total(ctx, req.spending, req.fee, req.coin)
             progress.report_init()
-        elif isinstance(req, UiConfirmFeeOverThreshold):
+        elif isinstance(req, helpers.UiConfirmFeeOverThreshold):
             res = await layout.confirm_feeoverthreshold(ctx, req.fee, req.coin)
             progress.report_init()
-        elif isinstance(req, UiConfirmForeignAddress):
+        elif isinstance(req, helpers.UiConfirmForeignAddress):
             res = await paths.show_path_warning(ctx, req.address_n)
         else:
             raise TypeError("Invalid signing instruction")
diff --git a/src/apps/wallet/sign_tx/decred_prefix_hasher.py b/src/apps/wallet/sign_tx/decred.py
similarity index 100%
rename from src/apps/wallet/sign_tx/decred_prefix_hasher.py
rename to src/apps/wallet/sign_tx/decred.py
diff --git a/src/apps/wallet/sign_tx/helpers.py b/src/apps/wallet/sign_tx/helpers.py
index b9bf83babe..e8f6a42d9b 100644
--- a/src/apps/wallet/sign_tx/helpers.py
+++ b/src/apps/wallet/sign_tx/helpers.py
@@ -12,6 +12,7 @@ from trezor.messages.TxInputType import TxInputType
 from trezor.messages.TxOutputBinType import TxOutputBinType
 from trezor.messages.TxOutputType import TxOutputType
 from trezor.messages.TxRequest import TxRequest
+from trezor.utils import obj_eq
 
 from apps.common.coininfo import CoinInfo
 
@@ -24,6 +25,8 @@ class UiConfirmOutput:
         self.output = output
         self.coin = coin
 
+    __eq__ = obj_eq
+
 
 class UiConfirmTotal:
     def __init__(self, spending: int, fee: int, coin: CoinInfo):
@@ -31,17 +34,23 @@ class UiConfirmTotal:
         self.fee = fee
         self.coin = coin
 
+    __eq__ = obj_eq
+
 
 class UiConfirmFeeOverThreshold:
     def __init__(self, fee: int, coin: CoinInfo):
         self.fee = fee
         self.coin = coin
 
+    __eq__ = obj_eq
+
 
 class UiConfirmForeignAddress:
     def __init__(self, address_n: list):
         self.address_n = address_n
 
+    __eq__ = obj_eq
+
 
 def confirm_output(output: TxOutputType, coin: CoinInfo):
     return (yield UiConfirmOutput(output, coin))
diff --git a/src/apps/wallet/sign_tx/signing.py b/src/apps/wallet/sign_tx/signing.py
index f72623fa22..ef37fbae38 100644
--- a/src/apps/wallet/sign_tx/signing.py
+++ b/src/apps/wallet/sign_tx/signing.py
@@ -1,35 +1,30 @@
 from micropython import const
 
+from trezor import utils
 from trezor.crypto import base58, bip32, cashaddr, der
 from trezor.crypto.curve import secp256k1
 from trezor.crypto.hashlib import blake256, sha256
-from trezor.messages import OutputScriptType
+from trezor.messages import FailureType, InputScriptType, OutputScriptType
+from trezor.messages.SignTx import SignTx
+from trezor.messages.TxInputType import TxInputType
+from trezor.messages.TxOutputBinType import TxOutputBinType
+from trezor.messages.TxOutputType import TxOutputType
+from trezor.messages.TxRequest import TxRequest
 from trezor.messages.TxRequestDetailsType import TxRequestDetailsType
 from trezor.messages.TxRequestSerializedType import TxRequestSerializedType
-from trezor.utils import HashWriter
 
-from apps.common import address_type, coins
-from apps.common.coininfo import CoinInfo
-from apps.common.writers import empty_bytearray
-from apps.wallet.sign_tx import progress
-from apps.wallet.sign_tx.addresses import *
-from apps.wallet.sign_tx.decred_prefix_hasher import (
-    DECRED_SERIALIZE_NO_WITNESS,
-    DECRED_SERIALIZE_WITNESS_SIGNING,
-    DECRED_SIGHASHALL,
-    DecredPrefixHasher,
-)
-from apps.wallet.sign_tx.helpers import *
-from apps.wallet.sign_tx.multisig import *
-from apps.wallet.sign_tx.scripts import *
-from apps.wallet.sign_tx.segwit_bip143 import Bip143, Bip143Error  # noqa:F401
-from apps.wallet.sign_tx.tx_weight_calculator import *
-from apps.wallet.sign_tx.writers import *
-from apps.wallet.sign_tx.zcash import (  # noqa:F401
-    OVERWINTERED,
-    ZcashError,
-    Zip143,
-    Zip243,
+from apps.common import address_type, coininfo, coins, seed
+from apps.wallet.sign_tx import (
+    addresses,
+    decred,
+    helpers,
+    multisig,
+    progress,
+    scripts,
+    segwit_bip143,
+    tx_weight,
+    writers,
+    zcash,
 )
 
 # the number of bip32 levels used in a wallet (chain and address)
@@ -58,32 +53,32 @@ class SigningError(ValueError):
 # - check inputs, previous transactions, and outputs
 # - ask for confirmations
 # - check fee
-async def check_tx_fee(tx: SignTx, root: bip32.HDNode):
+async def check_tx_fee(tx: SignTx, keychain: seed.Keychain):
     coin = coins.by_name(tx.coin_name)
 
     # h_first is used to make sure the inputs and outputs streamed in Phase 1
     # are the same as in Phase 2.  it is thus not required to fully hash the
     # tx, as the SignTx info is streamed only once
-    h_first = HashWriter(sha256())  # not a real tx hash
+    h_first = utils.HashWriter(sha256())  # not a real tx hash
 
     if coin.decred:
-        hash143 = DecredPrefixHasher(tx)  # pseudo bip143 prefix hashing
+        hash143 = decred.DecredPrefixHasher(tx)  # pseudo BIP-0143 prefix hashing
         tx_ser = TxRequestSerializedType()
     elif tx.overwintered:
         if tx.version == 3:
-            hash143 = Zip143()  # ZIP-0143 transaction hashing
+            hash143 = zcash.Zip143()  # ZIP-0143 transaction hashing
         elif tx.version == 4:
-            hash143 = Zip243()  # ZIP-0243 transaction hashing
+            hash143 = zcash.Zip243()  # ZIP-0243 transaction hashing
         else:
             raise SigningError(
                 FailureType.DataError,
                 "Unsupported version for overwintered transaction",
             )
     else:
-        hash143 = Bip143()  # BIP-0143 transaction hashing
+        hash143 = segwit_bip143.Bip143()  # BIP-0143 transaction hashing
 
-    multifp = MultisigFingerprint()  # control checksum of multisig inputs
-    weight = TxWeightCalculator(tx.inputs_count, tx.outputs_count)
+    multifp = multisig.MultisigFingerprint()  # control checksum of multisig inputs
+    weight = tx_weight.TxWeightCalculator(tx.inputs_count, tx.outputs_count)
 
     total_in = 0  # sum of input amounts
     segwit_in = 0  # sum of segwit input amounts
@@ -100,15 +95,15 @@ async def check_tx_fee(tx: SignTx, root: bip32.HDNode):
     for i in range(tx.inputs_count):
         progress.advance()
         # STAGE_REQUEST_1_INPUT
-        txi = await request_tx_input(tx_req, i)
+        txi = await helpers.request_tx_input(tx_req, i)
         wallet_path = input_extract_wallet_path(txi, wallet_path)
-        write_tx_input_check(h_first, txi)
+        writers.write_tx_input_check(h_first, txi)
         weight.add_input(txi)
         hash143.add_prevouts(txi)  # all inputs are included (non-segwit as well)
         hash143.add_sequence(txi)
 
-        if not validate_full_path(txi.address_n, coin, txi.script_type):
-            await confirm_foreign_address(txi.address_n)
+        if not addresses.validate_full_path(txi.address_n, coin, txi.script_type):
+            await helpers.confirm_foreign_address(txi.address_n)
 
         if txi.multisig:
             multifp.add(txi.multisig)
@@ -149,10 +144,10 @@ async def check_tx_fee(tx: SignTx, root: bip32.HDNode):
             raise SigningError(FailureType.DataError, "Wrong input script type")
 
         if coin.decred:
-            w_txi = empty_bytearray(8 if i == 0 else 0 + 9 + len(txi.prev_hash))
+            w_txi = writers.empty_bytearray(8 if i == 0 else 0 + 9 + len(txi.prev_hash))
             if i == 0:  # serializing first input => prepend headers
-                write_bytes(w_txi, get_tx_header(coin, tx))
-            write_tx_input_decred(w_txi, txi)
+                writers.write_bytes(w_txi, get_tx_header(coin, tx))
+            writers.write_tx_input_decred(w_txi, txi)
             tx_ser.serialized_tx = w_txi
             tx_req.serialized = tx_ser
 
@@ -161,15 +156,15 @@ async def check_tx_fee(tx: SignTx, root: bip32.HDNode):
 
     for o in range(tx.outputs_count):
         # STAGE_REQUEST_3_OUTPUT
-        txo = await request_tx_output(tx_req, o)
+        txo = await helpers.request_tx_output(tx_req, o)
         txo_bin.amount = txo.amount
-        txo_bin.script_pubkey = output_derive_script(txo, coin, root)
+        txo_bin.script_pubkey = output_derive_script(txo, coin, keychain)
         weight.add_output(txo_bin.script_pubkey)
 
-        if change_out == 0 and is_change(txo, wallet_path, segwit_in, multifp):
+        if change_out == 0 and output_is_change(txo, wallet_path, segwit_in, multifp):
             # output is change and does not need confirmation
             change_out = txo.amount
-        elif not await confirm_output(txo, coin):
+        elif not await helpers.confirm_output(txo, coin):
             raise SigningError(FailureType.ActionCancelled, "Output cancelled")
 
         if coin.decred:
@@ -180,15 +175,17 @@ async def check_tx_fee(tx: SignTx, root: bip32.HDNode):
                 )
             txo_bin.decred_script_version = txo.decred_script_version
 
-            w_txo_bin = empty_bytearray(4 + 8 + 2 + 4 + len(txo_bin.script_pubkey))
+            w_txo_bin = writers.empty_bytearray(
+                4 + 8 + 2 + 4 + len(txo_bin.script_pubkey)
+            )
             if o == 0:  # serializing first output => prepend outputs count
-                write_varint(w_txo_bin, tx.outputs_count)
-            write_tx_output(w_txo_bin, txo_bin)
+                writers.write_varint(w_txo_bin, tx.outputs_count)
+            writers.write_tx_output(w_txo_bin, txo_bin)
             tx_ser.serialized_tx = w_txo_bin
             tx_req.serialized = tx_ser
             hash143.set_last_output_bytes(w_txo_bin)
 
-        write_tx_output(h_first, txo_bin)
+        writers.write_tx_output(h_first, txo_bin)
         hash143.add_output(txo_bin)
         total_out += txo_bin.amount
 
@@ -198,10 +195,10 @@ async def check_tx_fee(tx: SignTx, root: bip32.HDNode):
 
     # fee > (coin.maxfee per byte * tx size)
     if fee > (coin.maxfee_kb / 1000) * (weight.get_total() / 4):
-        if not await confirm_feeoverthreshold(fee, coin):
+        if not await helpers.confirm_feeoverthreshold(fee, coin):
             raise SigningError(FailureType.ActionCancelled, "Signing cancelled")
 
-    if not await confirm_total(total_in - change_out, fee, coin):
+    if not await helpers.confirm_total(total_in - change_out, fee, coin):
         raise SigningError(FailureType.ActionCancelled, "Total cancelled")
 
     if coin.decred:
@@ -210,14 +207,16 @@ async def check_tx_fee(tx: SignTx, root: bip32.HDNode):
     return h_first, hash143, segwit, total_in, wallet_path
 
 
-async def sign_tx(tx: SignTx, root: bip32.HDNode):
-    tx = sanitize_sign_tx(tx)
+async def sign_tx(tx: SignTx, keychain: seed.Keychain):
+    tx = helpers.sanitize_sign_tx(tx)
 
     progress.init(tx.inputs_count, tx.outputs_count)
 
     # Phase 1
 
-    h_first, hash143, segwit, authorized_in, wallet_path = await check_tx_fee(tx, root)
+    h_first, hash143, segwit, authorized_in, wallet_path = await check_tx_fee(
+        tx, keychain
+    )
 
     # Phase 2
     # - sign inputs
@@ -242,34 +241,30 @@ async def sign_tx(tx: SignTx, root: bip32.HDNode):
 
         if segwit[i_sign]:
             # STAGE_REQUEST_SEGWIT_INPUT
-            txi_sign = await request_tx_input(tx_req, i_sign)
+            txi_sign = await helpers.request_tx_input(tx_req, i_sign)
 
-            is_segwit = (
-                txi_sign.script_type == InputScriptType.SPENDWITNESS
-                or txi_sign.script_type == InputScriptType.SPENDP2SHWITNESS
-            )
-            if not is_segwit:
+            if not input_is_segwit(txi_sign):
                 raise SigningError(
                     FailureType.ProcessError, "Transaction has changed during signing"
                 )
             input_check_wallet_path(txi_sign, wallet_path)
 
-            key_sign = node_derive(root, txi_sign.address_n)
+            key_sign = keychain.derive(txi_sign.address_n, coin.curve_name)
             key_sign_pub = key_sign.public_key()
             txi_sign.script_sig = input_derive_script(coin, txi_sign, key_sign_pub)
 
-            w_txi = empty_bytearray(
+            w_txi = writers.empty_bytearray(
                 7 + len(txi_sign.prev_hash) + 4 + len(txi_sign.script_sig) + 4
             )
             if i_sign == 0:  # serializing first input => prepend headers
-                write_bytes(w_txi, get_tx_header(coin, tx, True))
-            write_tx_input(w_txi, txi_sign)
+                writers.write_bytes(w_txi, get_tx_header(coin, tx, True))
+            writers.write_tx_input(w_txi, txi_sign)
             tx_ser.serialized_tx = w_txi
             tx_req.serialized = tx_ser
 
         elif coin.force_bip143 or tx.overwintered:
             # STAGE_REQUEST_SEGWIT_INPUT
-            txi_sign = await request_tx_input(tx_req, i_sign)
+            txi_sign = await helpers.request_tx_input(tx_req, i_sign)
             input_check_wallet_path(txi_sign, wallet_path)
 
             is_bip143 = (
@@ -282,19 +277,19 @@ async def sign_tx(tx: SignTx, root: bip32.HDNode):
                 )
             authorized_in -= txi_sign.amount
 
-            key_sign = node_derive(root, txi_sign.address_n)
+            key_sign = keychain.derive(txi_sign.address_n, coin.curve_name)
             key_sign_pub = key_sign.public_key()
             hash143_hash = hash143.preimage_hash(
                 coin,
                 tx,
                 txi_sign,
-                ecdsa_hash_pubkey(key_sign_pub, coin),
+                addresses.ecdsa_hash_pubkey(key_sign_pub, coin),
                 get_hash_type(coin),
             )
 
-            # if multisig, check if singing with a key that is included in multisig
+            # if multisig, check if signing with a key that is included in multisig
             if txi_sign.multisig:
-                multisig_pubkey_index(txi_sign.multisig, key_sign_pub)
+                multisig.multisig_pubkey_index(txi_sign.multisig, key_sign_pub)
 
             signature = ecdsa_sign(key_sign, hash143_hash)
             tx_ser.signature_index = i_sign
@@ -304,56 +299,59 @@ async def sign_tx(tx: SignTx, root: bip32.HDNode):
             txi_sign.script_sig = input_derive_script(
                 coin, txi_sign, key_sign_pub, signature
             )
-            w_txi_sign = empty_bytearray(
+            w_txi_sign = writers.empty_bytearray(
                 5 + len(txi_sign.prev_hash) + 4 + len(txi_sign.script_sig) + 4
             )
             if i_sign == 0:  # serializing first input => prepend headers
-                write_bytes(w_txi_sign, get_tx_header(coin, tx))
-            write_tx_input(w_txi_sign, txi_sign)
+                writers.write_bytes(w_txi_sign, get_tx_header(coin, tx))
+            writers.write_tx_input(w_txi_sign, txi_sign)
             tx_ser.serialized_tx = w_txi_sign
 
             tx_req.serialized = tx_ser
 
         elif coin.decred:
-            txi_sign = await request_tx_input(tx_req, i_sign)
+            txi_sign = await helpers.request_tx_input(tx_req, i_sign)
 
             input_check_wallet_path(txi_sign, wallet_path)
 
-            key_sign = node_derive(root, txi_sign.address_n)
+            key_sign = keychain.derive(txi_sign.address_n, coin.curve_name)
             key_sign_pub = key_sign.public_key()
 
             if txi_sign.script_type == InputScriptType.SPENDMULTISIG:
-                prev_pkscript = output_script_multisig(
-                    multisig_get_pubkeys(txi_sign.multisig), txi_sign.multisig.m
+                prev_pkscript = scripts.output_script_multisig(
+                    multisig.multisig_get_pubkeys(txi_sign.multisig),
+                    txi_sign.multisig.m,
                 )
             elif txi_sign.script_type == InputScriptType.SPENDADDRESS:
-                prev_pkscript = output_script_p2pkh(
-                    ecdsa_hash_pubkey(key_sign_pub, coin)
+                prev_pkscript = scripts.output_script_p2pkh(
+                    addresses.ecdsa_hash_pubkey(key_sign_pub, coin)
                 )
             else:
                 raise ValueError("Unknown input script type")
 
-            h_witness = HashWriter(blake256())
-            write_uint32(h_witness, tx.version | DECRED_SERIALIZE_WITNESS_SIGNING)
-            write_varint(h_witness, tx.inputs_count)
+            h_witness = utils.HashWriter(blake256())
+            writers.write_uint32(
+                h_witness, tx.version | decred.DECRED_SERIALIZE_WITNESS_SIGNING
+            )
+            writers.write_varint(h_witness, tx.inputs_count)
 
             for ii in range(tx.inputs_count):
                 if ii == i_sign:
-                    write_varint(h_witness, len(prev_pkscript))
-                    write_bytes(h_witness, prev_pkscript)
+                    writers.write_varint(h_witness, len(prev_pkscript))
+                    writers.write_bytes(h_witness, prev_pkscript)
                 else:
-                    write_varint(h_witness, 0)
+                    writers.write_varint(h_witness, 0)
 
-            witness_hash = get_tx_hash(
+            witness_hash = writers.get_tx_hash(
                 h_witness, double=coin.sign_hash_double, reverse=False
             )
 
-            h_sign = HashWriter(blake256())
-            write_uint32(h_sign, DECRED_SIGHASHALL)
-            write_bytes(h_sign, prefix_hash)
-            write_bytes(h_sign, witness_hash)
+            h_sign = utils.HashWriter(blake256())
+            writers.write_uint32(h_sign, decred.DECRED_SIGHASHALL)
+            writers.write_bytes(h_sign, prefix_hash)
+            writers.write_bytes(h_sign, witness_hash)
 
-            sig_hash = get_tx_hash(h_sign, double=coin.sign_hash_double)
+            sig_hash = writers.get_tx_hash(h_sign, double=coin.sign_hash_double)
             signature = ecdsa_sign(key_sign, sig_hash)
             tx_ser.signature_index = i_sign
             tx_ser.signature = signature
@@ -362,61 +360,62 @@ async def sign_tx(tx: SignTx, root: bip32.HDNode):
             txi_sign.script_sig = input_derive_script(
                 coin, txi_sign, key_sign_pub, signature
             )
-            w_txi_sign = empty_bytearray(
+            w_txi_sign = writers.empty_bytearray(
                 8 + 4 + len(hash143.get_last_output_bytes())
                 if i_sign == 0
                 else 0 + 16 + 4 + len(txi_sign.script_sig)
             )
 
             if i_sign == 0:
-                write_bytes(w_txi_sign, hash143.get_last_output_bytes())
-                write_uint32(w_txi_sign, tx.lock_time)
-                write_uint32(w_txi_sign, tx.expiry)
-                write_varint(w_txi_sign, tx.inputs_count)
+                writers.write_bytes(w_txi_sign, hash143.get_last_output_bytes())
+                writers.write_uint32(w_txi_sign, tx.lock_time)
+                writers.write_uint32(w_txi_sign, tx.expiry)
+                writers.write_varint(w_txi_sign, tx.inputs_count)
 
-            write_tx_input_decred_witness(w_txi_sign, txi_sign)
+            writers.write_tx_input_decred_witness(w_txi_sign, txi_sign)
             tx_ser.serialized_tx = w_txi_sign
             tx_req.serialized = tx_ser
 
         else:
             # hash of what we are signing with this input
-            h_sign = HashWriter(sha256())
+            h_sign = utils.HashWriter(sha256())
             # same as h_first, checked before signing the digest
-            h_second = HashWriter(sha256())
+            h_second = utils.HashWriter(sha256())
 
             if tx.overwintered:
-                write_uint32(
-                    h_sign, tx.version | OVERWINTERED
+                writers.write_uint32(
+                    h_sign, tx.version | zcash.OVERWINTERED
                 )  # nVersion | fOverwintered
-                write_uint32(h_sign, tx.version_group_id)  # nVersionGroupId
+                writers.write_uint32(h_sign, tx.version_group_id)  # nVersionGroupId
             else:
-                write_uint32(h_sign, tx.version)  # nVersion
+                writers.write_uint32(h_sign, tx.version)  # nVersion
                 if tx.timestamp:
-                    write_uint32(h_sign, tx.timestamp)
+                    writers.write_uint32(h_sign, tx.timestamp)
 
-            write_varint(h_sign, tx.inputs_count)
+            writers.write_varint(h_sign, tx.inputs_count)
 
             for i in range(tx.inputs_count):
                 # STAGE_REQUEST_4_INPUT
-                txi = await request_tx_input(tx_req, i)
+                txi = await helpers.request_tx_input(tx_req, i)
                 input_check_wallet_path(txi, wallet_path)
-                write_tx_input_check(h_second, txi)
+                writers.write_tx_input_check(h_second, txi)
                 if i == i_sign:
                     txi_sign = txi
-                    key_sign = node_derive(root, txi.address_n)
+                    key_sign = keychain.derive(txi.address_n, coin.curve_name)
                     key_sign_pub = key_sign.public_key()
                     # for the signing process the script_sig is equal
                     # to the previous tx's scriptPubKey (P2PKH) or a redeem script (P2SH)
                     if txi_sign.script_type == InputScriptType.SPENDMULTISIG:
-                        txi_sign.script_sig = output_script_multisig(
-                            multisig_get_pubkeys(txi_sign.multisig), txi_sign.multisig.m
+                        txi_sign.script_sig = scripts.output_script_multisig(
+                            multisig.multisig_get_pubkeys(txi_sign.multisig),
+                            txi_sign.multisig.m,
                         )
                     elif txi_sign.script_type == InputScriptType.SPENDADDRESS:
-                        txi_sign.script_sig = output_script_p2pkh(
-                            ecdsa_hash_pubkey(key_sign_pub, coin)
+                        txi_sign.script_sig = scripts.output_script_p2pkh(
+                            addresses.ecdsa_hash_pubkey(key_sign_pub, coin)
                         )
                         if coin.bip115:
-                            txi_sign.script_sig += script_replay_protection_bip115(
+                            txi_sign.script_sig += scripts.script_replay_protection_bip115(
                                 txi_sign.prev_block_hash_bip115,
                                 txi_sign.prev_block_height_bip115,
                             )
@@ -426,38 +425,38 @@ async def sign_tx(tx: SignTx, root: bip32.HDNode):
                         )
                 else:
                     txi.script_sig = bytes()
-                write_tx_input(h_sign, txi)
+                writers.write_tx_input(h_sign, txi)
 
-            write_varint(h_sign, tx.outputs_count)
+            writers.write_varint(h_sign, tx.outputs_count)
 
             for o in range(tx.outputs_count):
                 # STAGE_REQUEST_4_OUTPUT
-                txo = await request_tx_output(tx_req, o)
+                txo = await helpers.request_tx_output(tx_req, o)
                 txo_bin.amount = txo.amount
-                txo_bin.script_pubkey = output_derive_script(txo, coin, root)
-                write_tx_output(h_second, txo_bin)
-                write_tx_output(h_sign, txo_bin)
+                txo_bin.script_pubkey = output_derive_script(txo, coin, keychain)
+                writers.write_tx_output(h_second, txo_bin)
+                writers.write_tx_output(h_sign, txo_bin)
 
-            write_uint32(h_sign, tx.lock_time)
+            writers.write_uint32(h_sign, tx.lock_time)
             if tx.overwintered:
-                write_uint32(h_sign, tx.expiry)  # expiryHeight
-                write_varint(h_sign, 0)  # nJoinSplit
+                writers.write_uint32(h_sign, tx.expiry)  # expiryHeight
+                writers.write_varint(h_sign, 0)  # nJoinSplit
 
-            write_uint32(h_sign, get_hash_type(coin))
+            writers.write_uint32(h_sign, get_hash_type(coin))
 
             # check the control digests
-            if get_tx_hash(h_first, False) != get_tx_hash(h_second):
+            if writers.get_tx_hash(h_first, False) != writers.get_tx_hash(h_second):
                 raise SigningError(
                     FailureType.ProcessError, "Transaction has changed during signing"
                 )
 
-            # if multisig, check if singing with a key that is included in multisig
+            # if multisig, check if signing with a key that is included in multisig
             if txi_sign.multisig:
-                multisig_pubkey_index(txi_sign.multisig, key_sign_pub)
+                multisig.multisig_pubkey_index(txi_sign.multisig, key_sign_pub)
 
             # compute the signature from the tx digest
             signature = ecdsa_sign(
-                key_sign, get_tx_hash(h_sign, double=coin.sign_hash_double)
+                key_sign, writers.get_tx_hash(h_sign, double=coin.sign_hash_double)
             )
             tx_ser.signature_index = i_sign
             tx_ser.signature = signature
@@ -466,31 +465,31 @@ async def sign_tx(tx: SignTx, root: bip32.HDNode):
             txi_sign.script_sig = input_derive_script(
                 coin, txi_sign, key_sign_pub, signature
             )
-            w_txi_sign = empty_bytearray(
+            w_txi_sign = writers.empty_bytearray(
                 5 + len(txi_sign.prev_hash) + 4 + len(txi_sign.script_sig) + 4
             )
             if i_sign == 0:  # serializing first input => prepend headers
-                write_bytes(w_txi_sign, get_tx_header(coin, tx))
-            write_tx_input(w_txi_sign, txi_sign)
+                writers.write_bytes(w_txi_sign, get_tx_header(coin, tx))
+            writers.write_tx_input(w_txi_sign, txi_sign)
             tx_ser.serialized_tx = w_txi_sign
 
             tx_req.serialized = tx_ser
 
     if coin.decred:
-        return await request_tx_finish(tx_req)
+        return await helpers.request_tx_finish(tx_req)
 
     for o in range(tx.outputs_count):
         progress.advance()
         # STAGE_REQUEST_5_OUTPUT
-        txo = await request_tx_output(tx_req, o)
+        txo = await helpers.request_tx_output(tx_req, o)
         txo_bin.amount = txo.amount
-        txo_bin.script_pubkey = output_derive_script(txo, coin, root)
+        txo_bin.script_pubkey = output_derive_script(txo, coin, keychain)
 
         # serialize output
-        w_txo_bin = empty_bytearray(5 + 8 + 5 + len(txo_bin.script_pubkey) + 4)
+        w_txo_bin = writers.empty_bytearray(5 + 8 + 5 + len(txo_bin.script_pubkey) + 4)
         if o == 0:  # serializing first output => prepend outputs count
-            write_varint(w_txo_bin, tx.outputs_count)
-        write_tx_output(w_txo_bin, txo_bin)
+            writers.write_varint(w_txo_bin, tx.outputs_count)
+        writers.write_tx_output(w_txo_bin, txo_bin)
 
         tx_ser.signature_index = None
         tx_ser.signature = None
@@ -504,38 +503,38 @@ async def sign_tx(tx: SignTx, root: bip32.HDNode):
         progress.advance()
         if segwit[i]:
             # STAGE_REQUEST_SEGWIT_WITNESS
-            txi = await request_tx_input(tx_req, i)
+            txi = await helpers.request_tx_input(tx_req, i)
             input_check_wallet_path(txi, wallet_path)
 
-            is_segwit = (
-                txi.script_type == InputScriptType.SPENDWITNESS
-                or txi.script_type == InputScriptType.SPENDP2SHWITNESS
-            )
-            if not is_segwit or txi.amount > authorized_in:
+            if not input_is_segwit(txi) or txi.amount > authorized_in:
                 raise SigningError(
                     FailureType.ProcessError, "Transaction has changed during signing"
                 )
             authorized_in -= txi.amount
 
-            key_sign = node_derive(root, txi.address_n)
+            key_sign = keychain.derive(txi.address_n, coin.curve_name)
             key_sign_pub = key_sign.public_key()
             hash143_hash = hash143.preimage_hash(
                 coin,
                 tx,
                 txi,
-                ecdsa_hash_pubkey(key_sign_pub, coin),
+                addresses.ecdsa_hash_pubkey(key_sign_pub, coin),
                 get_hash_type(coin),
             )
 
             signature = ecdsa_sign(key_sign, hash143_hash)
             if txi.multisig:
                 # find out place of our signature based on the pubkey
-                signature_index = multisig_pubkey_index(txi.multisig, key_sign_pub)
-                witness = witness_p2wsh(
+                signature_index = multisig.multisig_pubkey_index(
+                    txi.multisig, key_sign_pub
+                )
+                witness = scripts.witness_p2wsh(
                     txi.multisig, signature, signature_index, get_hash_type(coin)
                 )
             else:
-                witness = witness_p2wpkh(signature, key_sign_pub, get_hash_type(coin))
+                witness = scripts.witness_p2wpkh(
+                    signature, key_sign_pub, get_hash_type(coin)
+                )
 
             tx_ser.serialized_tx = witness
             tx_ser.signature_index = i
@@ -547,66 +546,68 @@ async def sign_tx(tx: SignTx, root: bip32.HDNode):
 
         tx_req.serialized = tx_ser
 
-    write_uint32(tx_ser.serialized_tx, tx.lock_time)
+    writers.write_uint32(tx_ser.serialized_tx, tx.lock_time)
 
     if tx.overwintered:
         if tx.version == 3:
-            write_uint32(tx_ser.serialized_tx, tx.expiry)  # expiryHeight
-            write_varint(tx_ser.serialized_tx, 0)  # nJoinSplit
+            writers.write_uint32(tx_ser.serialized_tx, tx.expiry)  # expiryHeight
+            writers.write_varint(tx_ser.serialized_tx, 0)  # nJoinSplit
         elif tx.version == 4:
-            write_uint32(tx_ser.serialized_tx, tx.expiry)  # expiryHeight
-            write_uint64(tx_ser.serialized_tx, 0)  # valueBalance
-            write_varint(tx_ser.serialized_tx, 0)  # nShieldedSpend
-            write_varint(tx_ser.serialized_tx, 0)  # nShieldedOutput
-            write_varint(tx_ser.serialized_tx, 0)  # nJoinSplit
+            writers.write_uint32(tx_ser.serialized_tx, tx.expiry)  # expiryHeight
+            writers.write_uint64(tx_ser.serialized_tx, 0)  # valueBalance
+            writers.write_varint(tx_ser.serialized_tx, 0)  # nShieldedSpend
+            writers.write_varint(tx_ser.serialized_tx, 0)  # nShieldedOutput
+            writers.write_varint(tx_ser.serialized_tx, 0)  # nJoinSplit
         else:
             raise SigningError(
                 FailureType.DataError,
                 "Unsupported version for overwintered transaction",
             )
 
-    await request_tx_finish(tx_req)
+    await helpers.request_tx_finish(tx_req)
 
 
 async def get_prevtx_output_value(
-    coin: CoinInfo, tx_req: TxRequest, prev_hash: bytes, prev_index: int
+    coin: coininfo.CoinInfo, tx_req: TxRequest, prev_hash: bytes, prev_index: int
 ) -> int:
     total_out = 0  # sum of output amounts
 
     # STAGE_REQUEST_2_PREV_META
-    tx = await request_tx_meta(tx_req, prev_hash)
+    tx = await helpers.request_tx_meta(tx_req, prev_hash)
 
     if coin.decred:
-        txh = HashWriter(blake256())
+        txh = utils.HashWriter(blake256())
     else:
-        txh = HashWriter(sha256())
+        txh = utils.HashWriter(sha256())
 
     if tx.overwintered:
-        write_uint32(txh, tx.version | OVERWINTERED)  # nVersion | fOverwintered
-        write_uint32(txh, tx.version_group_id)  # nVersionGroupId
+        writers.write_uint32(
+            txh, tx.version | zcash.OVERWINTERED
+        )  # nVersion | fOverwintered
+        writers.write_uint32(txh, tx.version_group_id)  # nVersionGroupId
     elif coin.decred:
-        write_uint32(txh, tx.version | DECRED_SERIALIZE_NO_WITNESS)
+        writers.write_uint32(txh, tx.version | decred.DECRED_SERIALIZE_NO_WITNESS)
     else:
-        write_uint32(txh, tx.version)  # nVersion
+        writers.write_uint32(txh, tx.version)  # nVersion
         if tx.timestamp:
-            write_uint32(txh, tx.timestamp)
+            writers.write_uint32(txh, tx.timestamp)
 
-    write_varint(txh, tx.inputs_cnt)
+    writers.write_varint(txh, tx.inputs_cnt)
 
     for i in range(tx.inputs_cnt):
         # STAGE_REQUEST_2_PREV_INPUT
-        txi = await request_tx_input(tx_req, i, prev_hash)
+        txi = await helpers.request_tx_input(tx_req, i, prev_hash)
         if coin.decred:
-            write_tx_input_decred(txh, txi)
+            writers.write_tx_input_decred(txh, txi)
         else:
-            write_tx_input(txh, txi)
+            writers.write_tx_input(txh, txi)
 
-    write_varint(txh, tx.outputs_cnt)
+    writers.write_varint(txh, tx.outputs_cnt)
 
     for o in range(tx.outputs_cnt):
         # STAGE_REQUEST_2_PREV_OUTPUT
-        txo_bin = await request_tx_output(tx_req, o, prev_hash)
-        write_tx_output(txh, txo_bin)
+        txo_bin = await helpers.request_tx_output(tx_req, o, prev_hash)
+        writers.write_tx_output(txh, txo_bin)
         if o == prev_index:
             total_out += txo_bin.amount
             if (
@@ -619,19 +620,22 @@ async def get_prevtx_output_value(
                     "Cannot use utxo that has script_version != 0",
                 )
 
-    write_uint32(txh, tx.lock_time)
+    writers.write_uint32(txh, tx.lock_time)
 
     if tx.overwintered or coin.decred:
-        write_uint32(txh, tx.expiry)
+        writers.write_uint32(txh, tx.expiry)
 
     ofs = 0
     while ofs < tx.extra_data_len:
         size = min(1024, tx.extra_data_len - ofs)
-        data = await request_tx_extra_data(tx_req, ofs, size, prev_hash)
-        write_bytes(txh, data)
+        data = await helpers.request_tx_extra_data(tx_req, ofs, size, prev_hash)
+        writers.write_bytes(txh, data)
         ofs += len(data)
 
-    if get_tx_hash(txh, double=coin.sign_hash_double, reverse=True) != prev_hash:
+    if (
+        writers.get_tx_hash(txh, double=coin.sign_hash_double, reverse=True)
+        != prev_hash
+    ):
         raise SigningError(FailureType.ProcessError, "Encountered invalid prev_hash")
 
     return total_out
@@ -641,7 +645,7 @@ async def get_prevtx_output_value(
 # ===
 
 
-def get_hash_type(coin: CoinInfo) -> int:
+def get_hash_type(coin: coininfo.CoinInfo) -> int:
     SIGHASH_FORKID = const(0x40)
     SIGHASH_ALL = const(0x01)
     hashtype = SIGHASH_ALL
@@ -650,19 +654,21 @@ def get_hash_type(coin: CoinInfo) -> int:
     return hashtype
 
 
-def get_tx_header(coin: CoinInfo, tx: SignTx, segwit: bool = False):
+def get_tx_header(coin: coininfo.CoinInfo, tx: SignTx, segwit: bool = False):
     w_txi = bytearray()
     if tx.overwintered:
-        write_uint32(w_txi, tx.version | OVERWINTERED)  # nVersion | fOverwintered
-        write_uint32(w_txi, tx.version_group_id)  # nVersionGroupId
+        writers.write_uint32(
+            w_txi, tx.version | zcash.OVERWINTERED
+        )  # nVersion | fOverwintered
+        writers.write_uint32(w_txi, tx.version_group_id)  # nVersionGroupId
     else:
-        write_uint32(w_txi, tx.version)  # nVersion
+        writers.write_uint32(w_txi, tx.version)  # nVersion
         if tx.timestamp:
-            write_uint32(w_txi, tx.timestamp)
+            writers.write_uint32(w_txi, tx.timestamp)
     if segwit:
-        write_varint(w_txi, 0x00)  # segwit witness marker
-        write_varint(w_txi, 0x01)  # segwit witness flag
-    write_varint(w_txi, tx.inputs_count)
+        writers.write_varint(w_txi, 0x00)  # segwit witness marker
+        writers.write_varint(w_txi, 0x01)  # segwit witness flag
+    writers.write_varint(w_txi, tx.inputs_count)
     return w_txi
 
 
@@ -670,7 +676,9 @@ def get_tx_header(coin: CoinInfo, tx: SignTx, segwit: bool = False):
 # ===
 
 
-def output_derive_script(o: TxOutputType, coin: CoinInfo, root: bip32.HDNode) -> bytes:
+def output_derive_script(
+    o: TxOutputType, coin: coininfo.CoinInfo, keychain: seed.Keychain
+) -> bytes:
 
     if o.script_type == OutputScriptType.PAYTOOPRETURN:
         # op_return output
@@ -678,21 +686,21 @@ def output_derive_script(o: TxOutputType, coin: CoinInfo, root: bip32.HDNode) ->
             raise SigningError(
                 FailureType.DataError, "OP_RETURN output with non-zero amount"
             )
-        return output_script_paytoopreturn(o.op_return_data)
+        return scripts.output_script_paytoopreturn(o.op_return_data)
 
     if o.address_n:
         # change output
         if o.address:
             raise SigningError(FailureType.DataError, "Address in change output")
-        o.address = get_address_for_change(o, coin, root)
+        o.address = get_address_for_change(o, coin, keychain)
     else:
         if not o.address:
             raise SigningError(FailureType.DataError, "Missing address")
 
     if coin.bech32_prefix and o.address.startswith(coin.bech32_prefix):
         # p2wpkh or p2wsh
-        witprog = decode_bech32_address(coin.bech32_prefix, o.address)
-        return output_script_native_p2wpkh_or_p2wsh(witprog)
+        witprog = addresses.decode_bech32_address(coin.bech32_prefix, o.address)
+        return scripts.output_script_native_p2wpkh_or_p2wsh(witprog)
 
     if coin.cashaddr_prefix is not None and o.address.startswith(
         coin.cashaddr_prefix + ":"
@@ -712,9 +720,9 @@ def output_derive_script(o: TxOutputType, coin: CoinInfo, root: bip32.HDNode) ->
     if address_type.check(coin.address_type, raw_address):
         # p2pkh
         pubkeyhash = address_type.strip(coin.address_type, raw_address)
-        script = output_script_p2pkh(pubkeyhash)
+        script = scripts.output_script_p2pkh(pubkeyhash)
         if coin.bip115:
-            script += script_replay_protection_bip115(
+            script += scripts.script_replay_protection_bip115(
                 o.block_hash_bip115, o.block_height_bip115
             )
         return script
@@ -722,9 +730,9 @@ def output_derive_script(o: TxOutputType, coin: CoinInfo, root: bip32.HDNode) ->
     elif address_type.check(coin.address_type_p2sh, raw_address):
         # p2sh
         scripthash = address_type.strip(coin.address_type_p2sh, raw_address)
-        script = output_script_p2sh(scripthash)
+        script = scripts.output_script_p2sh(scripthash)
         if coin.bip115:
-            script += script_replay_protection_bip115(
+            script += scripts.script_replay_protection_bip115(
                 o.block_hash_bip115, o.block_height_bip115
             )
         return script
@@ -732,7 +740,9 @@ def output_derive_script(o: TxOutputType, coin: CoinInfo, root: bip32.HDNode) ->
     raise SigningError(FailureType.DataError, "Invalid address type")
 
 
-def get_address_for_change(o: TxOutputType, coin: CoinInfo, root: bip32.HDNode):
+def get_address_for_change(
+    o: TxOutputType, coin: coininfo.CoinInfo, keychain: seed.Keychain
+):
     if o.script_type == OutputScriptType.PAYTOADDRESS:
         input_script_type = InputScriptType.SPENDADDRESS
     elif o.script_type == OutputScriptType.PAYTOMULTISIG:
@@ -743,17 +753,19 @@ def get_address_for_change(o: TxOutputType, coin: CoinInfo, root: bip32.HDNode):
         input_script_type = InputScriptType.SPENDP2SHWITNESS
     else:
         raise SigningError(FailureType.DataError, "Invalid script type")
-    return get_address(
-        input_script_type, coin, node_derive(root, o.address_n), o.multisig
-    )
+    node = keychain.derive(o.address_n, coin.curve_name)
+    return addresses.get_address(input_script_type, coin, node, o.multisig)
 
 
-def output_is_change(o: TxOutputType, wallet_path: list, segwit_in: int) -> bool:
-    is_segwit = (
-        o.script_type == OutputScriptType.PAYTOWITNESS
-        or o.script_type == OutputScriptType.PAYTOP2SHWITNESS
-    )
-    if is_segwit and o.amount > segwit_in:
+def output_is_change(
+    o: TxOutputType,
+    wallet_path: list,
+    segwit_in: int,
+    multifp: multisig.MultisigFingerprint,
+) -> bool:
+    if o.multisig and not multifp.matches(o.multisig):
+        return False
+    if output_is_segwit(o) and o.amount > segwit_in:
         # if the output is segwit, make sure it doesn't spend more than what the
         # segwit inputs paid.  this is to prevent user being tricked into
         # creating ANYONECANSPEND outputs before full segwit activation.
@@ -766,38 +778,49 @@ def output_is_change(o: TxOutputType, wallet_path: list, segwit_in: int) -> bool
     )
 
 
+def output_is_segwit(o: TxOutputType) -> bool:
+    return (
+        o.script_type == OutputScriptType.PAYTOWITNESS
+        or o.script_type == OutputScriptType.PAYTOP2SHWITNESS
+    )
+
+
 # Tx Inputs
 # ===
 
 
 def input_derive_script(
-    coin: CoinInfo, i: TxInputType, pubkey: bytes, signature: bytes = None
+    coin: coininfo.CoinInfo, i: TxInputType, pubkey: bytes, signature: bytes = None
 ) -> bytes:
     if i.script_type == InputScriptType.SPENDADDRESS:
         # p2pkh or p2sh
-        return input_script_p2pkh_or_p2sh(pubkey, signature, get_hash_type(coin))
+        return scripts.input_script_p2pkh_or_p2sh(
+            pubkey, signature, get_hash_type(coin)
+        )
 
     if i.script_type == InputScriptType.SPENDP2SHWITNESS:
         # p2wpkh or p2wsh using p2sh
 
         if i.multisig:
             # p2wsh in p2sh
-            pubkeys = multisig_get_pubkeys(i.multisig)
-            witness_script = output_script_multisig(pubkeys, i.multisig.m)
+            pubkeys = multisig.multisig_get_pubkeys(i.multisig)
+            witness_script = scripts.output_script_multisig(pubkeys, i.multisig.m)
             witness_script_hash = sha256(witness_script).digest()
-            return input_script_p2wsh_in_p2sh(witness_script_hash)
+            return scripts.input_script_p2wsh_in_p2sh(witness_script_hash)
 
         # p2wpkh in p2sh
-        return input_script_p2wpkh_in_p2sh(ecdsa_hash_pubkey(pubkey, coin))
+        return scripts.input_script_p2wpkh_in_p2sh(
+            addresses.ecdsa_hash_pubkey(pubkey, coin)
+        )
 
     elif i.script_type == InputScriptType.SPENDWITNESS:
         # native p2wpkh or p2wsh
-        return input_script_native_p2wpkh_or_p2wsh()
+        return scripts.input_script_native_p2wpkh_or_p2wsh()
 
     elif i.script_type == InputScriptType.SPENDMULTISIG:
         # p2sh multisig
-        signature_index = multisig_pubkey_index(i.multisig, pubkey)
-        return input_script_multisig(
+        signature_index = multisig.multisig_pubkey_index(i.multisig, pubkey)
+        return scripts.input_script_multisig(
             i.multisig, signature, signature_index, get_hash_type(coin), coin
         )
 
@@ -805,6 +828,13 @@ def input_derive_script(
         raise SigningError(FailureType.ProcessError, "Invalid script type")
 
 
+def input_is_segwit(i: TxInputType) -> bool:
+    return (
+        i.script_type == InputScriptType.SPENDWITNESS
+        or i.script_type == InputScriptType.SPENDP2SHWITNESS
+    )
+
+
 def input_extract_wallet_path(txi: TxInputType, wallet_path: list) -> list:
     if wallet_path is None:
         return None  # there was a mismatch in previous inputs
@@ -828,22 +858,7 @@ def input_check_wallet_path(txi: TxInputType, wallet_path: list) -> list:
         )
 
 
-def node_derive(root: bip32.HDNode, address_n: list) -> bip32.HDNode:
-    node = root.clone()
-    node.derive_path(address_n)
-    return node
-
-
 def ecdsa_sign(node: bip32.HDNode, digest: bytes) -> bytes:
     sig = secp256k1.sign(node.private_key(), digest)
     sigder = der.encode_seq((sig[1:33], sig[33:65]))
     return sigder
-
-
-def is_change(
-    txo: TxOutputType, wallet_path: list, segwit_in: int, multifp: MultisigFingerprint
-) -> bool:
-    if txo.multisig:
-        if not multifp.matches(txo.multisig):
-            return False
-    return output_is_change(txo, wallet_path, segwit_in)
diff --git a/src/apps/wallet/sign_tx/tx_weight_calculator.py b/src/apps/wallet/sign_tx/tx_weight.py
similarity index 100%
rename from src/apps/wallet/sign_tx/tx_weight_calculator.py
rename to src/apps/wallet/sign_tx/tx_weight.py
diff --git a/src/apps/wallet/sign_tx/writers.py b/src/apps/wallet/sign_tx/writers.py
index 6d6b954e2a..e8214cd6b4 100644
--- a/src/apps/wallet/sign_tx/writers.py
+++ b/src/apps/wallet/sign_tx/writers.py
@@ -3,7 +3,8 @@ from trezor.messages.TxInputType import TxInputType
 from trezor.messages.TxOutputBinType import TxOutputBinType
 from trezor.utils import ensure
 
-from apps.common.writers import (
+from apps.common.writers import (  # noqa: F401
+    empty_bytearray,
     write_bytes,
     write_bytes_reversed,
     write_uint8,
diff --git a/src/trezor/wire/__init__.py b/src/trezor/wire/__init__.py
index f48046a9e2..4aba1a3b40 100644
--- a/src/trezor/wire/__init__.py
+++ b/src/trezor/wire/__init__.py
@@ -3,12 +3,25 @@ from trezor import log, loop, messages, utils, workflow
 from trezor.wire import codec_v1
 from trezor.wire.errors import *
 
+from apps.common import seed
+
 workflow_handlers = {}
 
 
-def add(mtype, pkgname, modname, *args):
+def add(mtype, pkgname, modname, namespace=None):
     """Shortcut for registering a dynamically-imported Protobuf workflow."""
-    register(mtype, protobuf_workflow, import_workflow, pkgname, modname, *args)
+    if namespace is not None:
+        register(
+            mtype,
+            protobuf_workflow,
+            keychain_workflow,
+            namespace,
+            import_workflow,
+            pkgname,
+            modname,
+        )
+    else:
+        register(mtype, protobuf_workflow, import_workflow, pkgname, modname)
 
 
 def register(mtype, handler, *args):
@@ -133,10 +146,12 @@ async def session_handler(iface, sid):
             continue
         except Error as exc:
             # we log wire.Error as warning, not as exception
-            log.warning(__name__, "failure: %s", exc.message)
+            if __debug__:
+                log.warning(__name__, "failure: %s", exc.message)
         except Exception as exc:
             # sessions are never closed by raised exceptions
-            log.exception(__name__, exc)
+            if __debug__:
+                log.exception(__name__, exc)
 
         # read new message in next iteration
         reader = None
@@ -155,7 +170,7 @@ async def protobuf_workflow(ctx, reader, handler, *args):
         # respond with specific code and message
         await ctx.write(Failure(code=exc.code, message=exc.message))
         raise
-    except Exception:  # as exc:
+    except Exception:
         # respond with a generic code and message
         await ctx.write(
             Failure(code=FailureType.FirmwareError, message="Firmware error")
@@ -166,6 +181,15 @@ async def protobuf_workflow(ctx, reader, handler, *args):
         await ctx.write(res)
 
 
+async def keychain_workflow(ctx, req, namespace, handler, *args):
+    keychain = await seed.get_keychain(ctx, namespace)
+    args += (keychain,)
+    try:
+        return await handler(ctx, req, *args)
+    finally:
+        keychain.__del__()
+
+
 def import_workflow(ctx, req, pkgname, modname, *args):
     modpath = "%s.%s" % (pkgname, modname)
     module = __import__(modpath, None, None, (modname,), 0)
diff --git a/tests/test_apps.cardano.address.py b/tests/test_apps.cardano.address.py
index 23cac3f621..ee6fd3e2a0 100644
--- a/tests/test_apps.cardano.address.py
+++ b/tests/test_apps.cardano.address.py
@@ -8,6 +8,7 @@ from apps.cardano.address import (
     validate_full_path,
     derive_address_and_node
 )
+from apps.cardano.seed import Keychain
 from trezor.crypto import bip32
 
 
@@ -16,6 +17,9 @@ class TestCardanoAddress(unittest.TestCase):
         mnemonic = "all all all all all all all all all all all all"
         passphrase = ""
         node = bip32.from_mnemonic_cardano(mnemonic, passphrase)
+        node.derive_cardano(0x80000000 | 44)
+        node.derive_cardano(0x80000000 | 1815)
+        keychain = Keychain([0x80000000 | 44, 0x80000000 | 1815], node)
 
         addresses = [
             "Ae2tdPwUPEZ98eHFwxSsPBDz73amioKpr58Vw85mP1tMkzq8siaftiejJ3j",
@@ -25,7 +29,7 @@ class TestCardanoAddress(unittest.TestCase):
 
         for i, expected in enumerate(addresses):
             # 44'/1815'/0'/0/i'
-            address, _ = derive_address_and_node(node, [0x80000000 | 44, 0x80000000 | 1815, 0x80000000, 0, 0x80000000 + i])
+            address, _ = derive_address_and_node(keychain, [0x80000000 | 44, 0x80000000 | 1815, 0x80000000, 0, 0x80000000 + i])
             self.assertEqual(expected, address)
 
         nodes = [
@@ -50,7 +54,7 @@ class TestCardanoAddress(unittest.TestCase):
         ]
 
         for i, (priv, ext, pub, chain) in enumerate(nodes):
-            _, n = derive_address_and_node(node, [0x80000000 | 44, 0x80000000 | 1815, 0x80000000, 0, 0x80000000 + i])
+            _, n = derive_address_and_node(keychain, [0x80000000 | 44, 0x80000000 | 1815, 0x80000000, 0, 0x80000000 + i])
             self.assertEqual(hexlify(n.private_key()), priv)
             self.assertEqual(hexlify(n.private_key_ext()), ext)
             self.assertEqual(hexlify(seed.remove_ed25519_prefix(n.public_key())), pub)
@@ -60,6 +64,9 @@ class TestCardanoAddress(unittest.TestCase):
         mnemonic = "all all all all all all all all all all all all"
         passphrase = ""
         node = bip32.from_mnemonic_cardano(mnemonic, passphrase)
+        node.derive_cardano(0x80000000 | 44)
+        node.derive_cardano(0x80000000 | 1815)
+        keychain = Keychain([0x80000000 | 44, 0x80000000 | 1815], node)
 
         addresses = [
             "Ae2tdPwUPEZ5YUb8sM3eS8JqKgrRLzhiu71crfuH2MFtqaYr5ACNRdsswsZ",
@@ -69,7 +76,7 @@ class TestCardanoAddress(unittest.TestCase):
 
         for i, expected in enumerate(addresses):
             # 44'/1815'/0'/0/i
-            address, _ = derive_address_and_node(node, [0x80000000 | 44, 0x80000000 | 1815, 0x80000000, 0, i])
+            address, _ = derive_address_and_node(keychain, [0x80000000 | 44, 0x80000000 | 1815, 0x80000000, 0, i])
             self.assertEqual(address, expected)
 
         nodes = [
@@ -94,7 +101,7 @@ class TestCardanoAddress(unittest.TestCase):
         ]
 
         for i, (priv, ext, pub, chain) in enumerate(nodes):
-            _, n = derive_address_and_node(node, [0x80000000 | 44, 0x80000000 | 1815, 0x80000000, 0, i])
+            _, n = derive_address_and_node(keychain, [0x80000000 | 44, 0x80000000 | 1815, 0x80000000, 0, i])
             self.assertEqual(hexlify(n.private_key()), priv)
             self.assertEqual(hexlify(n.private_key_ext()), ext)
             self.assertEqual(hexlify(seed.remove_ed25519_prefix(n.public_key())), pub)
@@ -105,9 +112,12 @@ class TestCardanoAddress(unittest.TestCase):
         mnemonic = "all all all all all all all all all all all all"
         passphrase = ""
         node = bip32.from_mnemonic_cardano(mnemonic, passphrase)
+        node.derive_cardano(0x80000000 | 44)
+        node.derive_cardano(0x80000000 | 1815)
+        keychain = Keychain([0x80000000 | 44, 0x80000000 | 1815], node)
 
         # 44'/1815'
-        address, _ = derive_address_and_node(node, [0x80000000 | 44, 0x80000000 | 1815])
+        address, _ = derive_address_and_node(keychain, [0x80000000 | 44, 0x80000000 | 1815])
         self.assertEqual(address, "Ae2tdPwUPEZ2FGHX3yCKPSbSgyuuTYgMxNq652zKopxT4TuWvEd8Utd92w3")
 
         priv, ext, pub, chain = (
@@ -117,7 +127,7 @@ class TestCardanoAddress(unittest.TestCase):
             b"02ac67c59a8b0264724a635774ca2c242afa10d7ab70e2bf0a8f7d4bb10f1f7a"
         )
 
-        _, n = derive_address_and_node(node, [0x80000000 | 44, 0x80000000 | 1815])
+        _, n = derive_address_and_node(keychain, [0x80000000 | 44, 0x80000000 | 1815])
         self.assertEqual(hexlify(n.private_key()), priv)
         self.assertEqual(hexlify(n.private_key_ext()), ext)
         self.assertEqual(hexlify(seed.remove_ed25519_prefix(n.public_key())), pub)
diff --git a/tests/test_apps.cardano.get_public_key.py b/tests/test_apps.cardano.get_public_key.py
index e9b7fdfa49..33cdc4e8f6 100644
--- a/tests/test_apps.cardano.get_public_key.py
+++ b/tests/test_apps.cardano.get_public_key.py
@@ -1,5 +1,6 @@
 from common import *
 
+from apps.cardano.seed import Keychain
 from apps.cardano.get_public_key import _get_public_key
 from trezor.crypto import bip32
 from ubinascii import hexlify
@@ -10,6 +11,9 @@ class TestCardanoGetPublicKey(unittest.TestCase):
         mnemonic = "all all all all all all all all all all all all"
         passphrase = ""
         node = bip32.from_mnemonic_cardano(mnemonic, passphrase)
+        node.derive_cardano(0x80000000 | 44)
+        node.derive_cardano(0x80000000 | 1815)
+        keychain = Keychain([0x80000000 | 44, 0x80000000 | 1815], node)
 
         derivation_paths = [
             [0x80000000 | 44, 0x80000000 | 1815, 0x80000000, 0, 0x80000000],
@@ -40,7 +44,7 @@ class TestCardanoGetPublicKey(unittest.TestCase):
         ]
 
         for index, derivation_path in enumerate(derivation_paths):
-            key = _get_public_key(node, derivation_path)
+            key = _get_public_key(keychain, derivation_path)
 
             self.assertEqual(hexlify(key.node.public_key), public_keys[index])
             self.assertEqual(hexlify(key.node.chain_code), chain_codes[index])
diff --git a/tests/test_apps.ethereum.layout.py b/tests/test_apps.ethereum.layout.py
index c0e72b74f1..5da5746864 100644
--- a/tests/test_apps.ethereum.layout.py
+++ b/tests/test_apps.ethereum.layout.py
@@ -45,7 +45,7 @@ class TestEthereumLayout(unittest.TestCase):
         text = format_ethereum_amount(1000000000000000000, None, 61)
         self.assertEqual(text, '1 ETC')
         text = format_ethereum_amount(1000000000000000000, None, 31)
-        self.assertEqual(text, '1 tRSK')
+        self.assertEqual(text, '1 tRBTC')
 
         text = format_ethereum_amount(1000000000000000001, None, 1)
         self.assertEqual(text, '1.000000000000000001 ETH')
@@ -54,7 +54,7 @@ class TestEthereumLayout(unittest.TestCase):
         text = format_ethereum_amount(10000000000000000001, None, 61)
         self.assertEqual(text, '10.000000000000000001 ETC')
         text = format_ethereum_amount(1000000000000000001, None, 31)
-        self.assertEqual(text, '1.000000000000000001 tRSK')
+        self.assertEqual(text, '1.000000000000000001 tRBTC')
 
         # unknown chain
         text = format_ethereum_amount(1, None, 9999)
diff --git a/tests/test_apps.wallet.address.py b/tests/test_apps.wallet.address.py
index d39067ddbb..2df72c70ea 100644
--- a/tests/test_apps.wallet.address.py
+++ b/tests/test_apps.wallet.address.py
@@ -1,10 +1,19 @@
 from common import *
 from trezor.crypto import bip32, bip39
+from trezor.utils import HashWriter
 
 from apps.wallet.sign_tx.addresses import validate_full_path, validate_path_for_bitcoin_public_key
 from apps.common.paths import HARDENED
 from apps.common import coins
+from apps.wallet.sign_tx.addresses import *
 from apps.wallet.sign_tx.signing import *
+from apps.wallet.sign_tx.writers import *
+
+
+def node_derive(root, path):
+    node = root.clone()
+    node.derive_path(path)
+    return node
 
 
 class TestAddress(unittest.TestCase):
diff --git a/tests/test_apps.wallet.address_grs.py b/tests/test_apps.wallet.address_grs.py
index 404ddff04b..8aeb173e0c 100644
--- a/tests/test_apps.wallet.address_grs.py
+++ b/tests/test_apps.wallet.address_grs.py
@@ -1,10 +1,17 @@
 from common import *
 
 from apps.wallet.sign_tx.signing import *
+from apps.wallet.sign_tx.addresses import *
 from apps.common import coins
 from trezor.crypto import bip32, bip39
 
 
+def node_derive(root, path):
+    node = root.clone()
+    node.derive_path(path)
+    return node
+
+
 class TestAddressGRS(unittest.TestCase):
     # pylint: disable=C0301
 
diff --git a/tests/test_apps.wallet.segwit.bip143.native_p2wpkh.py b/tests/test_apps.wallet.segwit.bip143.native_p2wpkh.py
index f1e215bff1..5433367d3a 100644
--- a/tests/test_apps.wallet.segwit.bip143.native_p2wpkh.py
+++ b/tests/test_apps.wallet.segwit.bip143.native_p2wpkh.py
@@ -1,6 +1,7 @@
 from common import *
 
 from apps.wallet.sign_tx.signing import *
+from apps.wallet.sign_tx.segwit_bip143 import *
 from apps.common import coins
 from trezor.messages.SignTx import SignTx
 from trezor.messages.TxInputType import TxInputType
diff --git a/tests/test_apps.wallet.segwit.bip143.p2wpkh_in_p2sh.py b/tests/test_apps.wallet.segwit.bip143.p2wpkh_in_p2sh.py
index d8a9ba6478..652e82d199 100644
--- a/tests/test_apps.wallet.segwit.bip143.p2wpkh_in_p2sh.py
+++ b/tests/test_apps.wallet.segwit.bip143.p2wpkh_in_p2sh.py
@@ -1,6 +1,7 @@
 from common import *
 
 from apps.wallet.sign_tx.signing import *
+from apps.wallet.sign_tx.segwit_bip143 import *
 from apps.common import coins
 from trezor.messages.SignTx import SignTx
 from trezor.messages.TxInputType import TxInputType
diff --git a/tests/test_apps.wallet.segwit.signtx.native_p2wpkh.py b/tests/test_apps.wallet.segwit.signtx.native_p2wpkh.py
index c09f7d48ed..a2dbb8404c 100644
--- a/tests/test_apps.wallet.segwit.signtx.native_p2wpkh.py
+++ b/tests/test_apps.wallet.segwit.signtx.native_p2wpkh.py
@@ -1,7 +1,7 @@
 from common import *
 
 from trezor.utils import chunks
-from trezor.crypto import bip32, bip39
+from trezor.crypto import bip39
 from trezor.messages.SignTx import SignTx
 from trezor.messages.TxInputType import TxInputType
 from trezor.messages.TxOutputType import TxOutputType
@@ -15,7 +15,8 @@ from trezor.messages import InputScriptType
 from trezor.messages import OutputScriptType
 
 from apps.common import coins
-from apps.wallet.sign_tx import signing
+from apps.common.seed import Keychain
+from apps.wallet.sign_tx import helpers, signing
 
 
 class TestSignSegwitTxNativeP2WPKH(unittest.TestCase):
@@ -24,9 +25,7 @@ class TestSignSegwitTxNativeP2WPKH(unittest.TestCase):
     def test_send_native_p2wpkh(self):
 
         coin = coins.by_name('Testnet')
-
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, 'secp256k1')
 
         inp1 = TxInputType(
             # 49'/1'/0'/0/0" - tb1qqzv60m9ajw8drqulta4ld4gfx0rdh82un5s65s
@@ -61,22 +60,22 @@ class TestSignSegwitTxNativeP2WPKH(unittest.TestCase):
             TxRequest(request_type=TXINPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None)),
             TxAck(tx=TransactionType(inputs=[inp1])),
 
-            signing.UiConfirmForeignAddress(address_n=inp1.address_n),
+            helpers.UiConfirmForeignAddress(address_n=inp1.address_n),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
 
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=1, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out2])),
 
-            signing.UiConfirmOutput(out2, coin),
+            helpers.UiConfirmOutput(out2, coin),
             True,
 
-            signing.UiConfirmTotal(12300000, 11000, coin),
+            helpers.UiConfirmTotal(12300000, 11000, coin),
             True,
 
             # sign tx
@@ -113,18 +112,17 @@ class TestSignSegwitTxNativeP2WPKH(unittest.TestCase):
             )),
         ]
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
     def test_send_native_p2wpkh_change(self):
 
         coin = coins.by_name('Testnet')
-
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, 'secp256k1')
 
         inp1 = TxInputType(
             # 49'/1'/0'/0/0" - tb1qqzv60m9ajw8drqulta4ld4gfx0rdh82un5s65s
@@ -159,19 +157,19 @@ class TestSignSegwitTxNativeP2WPKH(unittest.TestCase):
             TxRequest(request_type=TXINPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None)),
             TxAck(tx=TransactionType(inputs=[inp1])),
 
-            signing.UiConfirmForeignAddress(address_n=inp1.address_n),
+            helpers.UiConfirmForeignAddress(address_n=inp1.address_n),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
 
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=1, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out2])),
 
-            signing.UiConfirmTotal(5000000 + 11000, 11000, coin),
+            helpers.UiConfirmTotal(5000000 + 11000, 11000, coin),
             True,
 
             # sign tx
@@ -209,21 +207,13 @@ class TestSignSegwitTxNativeP2WPKH(unittest.TestCase):
             )),
         ]
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
-    def assertEqualEx(self, a, b):
-        # hack to avoid adding __eq__ to signing.Ui* classes
-        if ((isinstance(a, signing.UiConfirmOutput) and isinstance(b, signing.UiConfirmOutput)) or
-                (isinstance(a, signing.UiConfirmTotal) and isinstance(b, signing.UiConfirmTotal)) or
-                (isinstance(a, signing.UiConfirmForeignAddress) and isinstance(b, signing.UiConfirmForeignAddress))):
-            return self.assertEqual(a.__dict__, b.__dict__)
-        else:
-            return self.assertEqual(a, b)
-
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/test_apps.wallet.segwit.signtx.native_p2wpkh_grs.py b/tests/test_apps.wallet.segwit.signtx.native_p2wpkh_grs.py
index 907cd81507..9ad58c17b6 100644
--- a/tests/test_apps.wallet.segwit.signtx.native_p2wpkh_grs.py
+++ b/tests/test_apps.wallet.segwit.signtx.native_p2wpkh_grs.py
@@ -1,7 +1,7 @@
 from common import *
 
 from trezor.utils import chunks
-from trezor.crypto import bip32, bip39
+from trezor.crypto import bip39
 from trezor.messages.SignTx import SignTx
 from trezor.messages.TxInputType import TxInputType
 from trezor.messages.TxOutputType import TxOutputType
@@ -15,7 +15,8 @@ from trezor.messages import InputScriptType
 from trezor.messages import OutputScriptType
 
 from apps.common import coins
-from apps.wallet.sign_tx import signing
+from apps.common.seed import Keychain
+from apps.wallet.sign_tx import helpers, signing
 
 # https://groestlsight-test.groestlcoin.org/api/tx/9b5c4859a8a31e69788cb4402812bb28f14ad71cbd8c60b09903478bc56f79a3
 class TestSignSegwitTxNativeP2WPKH_GRS(unittest.TestCase):
@@ -24,9 +25,7 @@ class TestSignSegwitTxNativeP2WPKH_GRS(unittest.TestCase):
     def test_send_native_p2wpkh(self):
 
         coin = coins.by_name('Groestlcoin Testnet')
-
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, coin.curve_name)
 
         inp1 = TxInputType(
             # 84'/1'/0'/0/0" - tgrs1qkvwu9g3k2pdxewfqr7syz89r3gj557l3ued7ja
@@ -64,16 +63,16 @@ class TestSignSegwitTxNativeP2WPKH_GRS(unittest.TestCase):
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
 
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=1, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out2])),
 
-            signing.UiConfirmOutput(out2, coin),
+            helpers.UiConfirmOutput(out2, coin),
             True,
 
-            signing.UiConfirmTotal(12300000, 11000, coin),
+            helpers.UiConfirmTotal(12300000, 11000, coin),
             True,
 
             # sign tx
@@ -110,18 +109,17 @@ class TestSignSegwitTxNativeP2WPKH_GRS(unittest.TestCase):
             )),
         ]
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
     def test_send_native_p2wpkh_change(self):
 
         coin = coins.by_name('Groestlcoin Testnet')
-
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, coin.curve_name)
 
         inp1 = TxInputType(
             # 84'/1'/0'/0/0" - tgrs1qkvwu9g3k2pdxewfqr7syz89r3gj557l3ued7ja
@@ -159,13 +157,13 @@ class TestSignSegwitTxNativeP2WPKH_GRS(unittest.TestCase):
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
 
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=1, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out2])),
 
-            signing.UiConfirmTotal(5000000 + 11000, 11000, coin),
+            helpers.UiConfirmTotal(5000000 + 11000, 11000, coin),
             True,
 
             # sign tx
@@ -203,20 +201,13 @@ class TestSignSegwitTxNativeP2WPKH_GRS(unittest.TestCase):
             )),
         ]
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
-    def assertEqualEx(self, a, b):
-        # hack to avoid adding __eq__ to signing.Ui* classes
-        if ((isinstance(a, signing.UiConfirmOutput) and isinstance(b, signing.UiConfirmOutput)) or
-                (isinstance(a, signing.UiConfirmTotal) and isinstance(b, signing.UiConfirmTotal))):
-            return self.assertEqual(a.__dict__, b.__dict__)
-        else:
-            return self.assertEqual(a, b)
-
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/test_apps.wallet.segwit.signtx.p2wpkh_in_p2sh.py b/tests/test_apps.wallet.segwit.signtx.p2wpkh_in_p2sh.py
index 208e72a042..bdb6a5391b 100644
--- a/tests/test_apps.wallet.segwit.signtx.p2wpkh_in_p2sh.py
+++ b/tests/test_apps.wallet.segwit.signtx.p2wpkh_in_p2sh.py
@@ -1,7 +1,7 @@
 from common import *
 
 from trezor.utils import chunks
-from trezor.crypto import bip32, bip39
+from trezor.crypto import bip39
 from trezor.messages.SignTx import SignTx
 from trezor.messages.TxInputType import TxInputType
 from trezor.messages.TxOutputType import TxOutputType
@@ -15,7 +15,8 @@ from trezor.messages import InputScriptType
 from trezor.messages import OutputScriptType
 
 from apps.common import coins
-from apps.wallet.sign_tx import signing
+from apps.common.seed import Keychain
+from apps.wallet.sign_tx import helpers, signing
 
 
 class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
@@ -24,9 +25,7 @@ class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
     def test_send_p2wpkh_in_p2sh(self):
 
         coin = coins.by_name('Testnet')
-
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, 'secp256k1')
 
         inp1 = TxInputType(
             # 49'/1'/0'/1/0" - 2N1LGaGg836mqSQqiuUBLfcyGBhyZbremDX
@@ -64,16 +63,16 @@ class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
 
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=1, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out2])),
 
-            signing.UiConfirmOutput(out2, coin),
+            helpers.UiConfirmOutput(out2, coin),
             True,
 
-            signing.UiConfirmTotal(123445789 + 11000, 11000, coin),
+            helpers.UiConfirmTotal(123445789 + 11000, 11000, coin),
             True,
 
             # sign tx
@@ -110,18 +109,17 @@ class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
             )),
         ]
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
     def test_send_p2wpkh_in_p2sh_change(self):
 
         coin = coins.by_name('Testnet')
-
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, 'secp256k1')
 
         inp1 = TxInputType(
             # 49'/1'/0'/1/0" - 2N1LGaGg836mqSQqiuUBLfcyGBhyZbremDX
@@ -160,14 +158,14 @@ class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
                       serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
 
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=1, tx_hash=None),
                       serialized=None),
             TxAck(tx=TransactionType(outputs=[out2])),
 
-            signing.UiConfirmTotal(12300000 + 11000, 11000, coin),
+            helpers.UiConfirmTotal(12300000 + 11000, 11000, coin),
             True,
 
             # sign tx
@@ -213,9 +211,10 @@ class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
             )),
         ]
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
@@ -224,9 +223,7 @@ class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
     def test_send_p2wpkh_in_p2sh_attack_amount(self):
 
         coin = coins.by_name('Testnet')
-
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, 'secp256k1')
 
         inp1 = TxInputType(
             # 49'/1'/0'/1/0" - 2N1LGaGg836mqSQqiuUBLfcyGBhyZbremDX
@@ -275,14 +272,14 @@ class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
                       serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
 
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=1, tx_hash=None),
                       serialized=None),
             TxAck(tx=TransactionType(outputs=[out2])),
 
-            signing.UiConfirmTotal(8, 0, coin),
+            helpers.UiConfirmTotal(8, 0, coin),
             True,
 
             TxRequest(request_type=TXINPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None),
@@ -322,26 +319,19 @@ class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
             TxRequest(request_type=TXFINISHED, details=None)
         ]
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         i = 0
         messages_count = int(len(messages) / 2)
         for request, response in chunks(messages, 2):
             if i == messages_count - 1:  # last message should throw SigningError
                 self.assertRaises(signing.SigningError, signer.send, request)
             else:
-                self.assertEqualEx(signer.send(request), response)
+                self.assertEqual(signer.send(request), response)
             i += 1
         with self.assertRaises(StopIteration):
             signer.send(None)
 
-    def assertEqualEx(self, a, b):
-        # hack to avoid adding __eq__ to signing.Ui* classes
-        if ((isinstance(a, signing.UiConfirmOutput) and isinstance(b, signing.UiConfirmOutput)) or
-                (isinstance(a, signing.UiConfirmTotal) and isinstance(b, signing.UiConfirmTotal))):
-            return self.assertEqual(a.__dict__, b.__dict__)
-        else:
-            return self.assertEqual(a, b)
-
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/test_apps.wallet.segwit.signtx.p2wpkh_in_p2sh_grs.py b/tests/test_apps.wallet.segwit.signtx.p2wpkh_in_p2sh_grs.py
index 6e8431ac5c..152142c2bb 100644
--- a/tests/test_apps.wallet.segwit.signtx.p2wpkh_in_p2sh_grs.py
+++ b/tests/test_apps.wallet.segwit.signtx.p2wpkh_in_p2sh_grs.py
@@ -1,7 +1,7 @@
 from common import *
 
 from trezor.utils import chunks
-from trezor.crypto import bip32, bip39
+from trezor.crypto import bip39
 from trezor.messages.SignTx import SignTx
 from trezor.messages.TxInputType import TxInputType
 from trezor.messages.TxOutputType import TxOutputType
@@ -15,7 +15,8 @@ from trezor.messages import InputScriptType
 from trezor.messages import OutputScriptType
 
 from apps.common import coins
-from apps.wallet.sign_tx import signing
+from apps.common.seed import Keychain
+from apps.wallet.sign_tx import helpers, signing
 
 # https://groestlsight-test.groestlcoin.org/api/tx/4ce0220004bdfe14e3dd49fd8636bcb770a400c0c9e9bff670b6a13bb8f15c72
 class TestSignSegwitTxP2WPKHInP2SH_GRS(unittest.TestCase):
@@ -24,9 +25,7 @@ class TestSignSegwitTxP2WPKHInP2SH_GRS(unittest.TestCase):
     def test_send_p2wpkh_in_p2sh(self):
 
         coin = coins.by_name('Groestlcoin Testnet')
-
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, coin.curve_name)
 
         inp1 = TxInputType(
             # 49'/1'/0'/1/0" - 2N1LGaGg836mqSQqiuUBLfcyGBhyZYBtBZ7
@@ -64,16 +63,16 @@ class TestSignSegwitTxP2WPKHInP2SH_GRS(unittest.TestCase):
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
 
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=1, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out2])),
 
-            signing.UiConfirmOutput(out2, coin),
+            helpers.UiConfirmOutput(out2, coin),
             True,
 
-            signing.UiConfirmTotal(123445789 + 11000, 11000, coin),
+            helpers.UiConfirmTotal(123445789 + 11000, 11000, coin),
             True,
 
             # sign tx
@@ -110,18 +109,17 @@ class TestSignSegwitTxP2WPKHInP2SH_GRS(unittest.TestCase):
             )),
         ]
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
     def test_send_p2wpkh_in_p2sh_change(self):
 
         coin = coins.by_name('Groestlcoin Testnet')
-
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, coin.curve_name)
 
         inp1 = TxInputType(
             # 49'/1'/0'/1/0" - 2N1LGaGg836mqSQqiuUBLfcyGBhyZYBtBZ7
@@ -160,14 +158,14 @@ class TestSignSegwitTxP2WPKHInP2SH_GRS(unittest.TestCase):
                       serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
 
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
 
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=1, tx_hash=None),
                       serialized=None),
             TxAck(tx=TransactionType(outputs=[out2])),
 
-            signing.UiConfirmTotal(12300000 + 11000, 11000, coin),
+            helpers.UiConfirmTotal(12300000 + 11000, 11000, coin),
             True,
 
             # sign tx
@@ -212,20 +210,13 @@ class TestSignSegwitTxP2WPKHInP2SH_GRS(unittest.TestCase):
             )),
         ]
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
-    def assertEqualEx(self, a, b):
-        # hack to avoid adding __eq__ to signing.Ui* classes
-        if ((isinstance(a, signing.UiConfirmOutput) and isinstance(b, signing.UiConfirmOutput)) or
-                (isinstance(a, signing.UiConfirmTotal) and isinstance(b, signing.UiConfirmTotal))):
-            return self.assertEqual(a.__dict__, b.__dict__)
-        else:
-            return self.assertEqual(a, b)
-
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/test_apps.wallet.signtx.fee_threshold.py b/tests/test_apps.wallet.signtx.fee_threshold.py
index cecaa6da35..4b4f1935f1 100644
--- a/tests/test_apps.wallet.signtx.fee_threshold.py
+++ b/tests/test_apps.wallet.signtx.fee_threshold.py
@@ -14,7 +14,8 @@ from trezor.messages.TxRequestDetailsType import TxRequestDetailsType
 from trezor.messages import OutputScriptType
 
 from apps.common import coins
-from apps.wallet.sign_tx import signing
+from apps.common.seed import Keychain
+from apps.wallet.sign_tx import helpers, signing
 
 
 class TestSignTxFeeThreshold(unittest.TestCase):
@@ -60,7 +61,7 @@ class TestSignTxFeeThreshold(unittest.TestCase):
 
             TxRequest(request_type=TXINPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None)),
             TxAck(tx=TransactionType(inputs=[inp1])),
-            signing.UiConfirmForeignAddress(address_n=inp1.address_n),
+            helpers.UiConfirmForeignAddress(address_n=inp1.address_n),
             True,
             TxRequest(request_type=TXMETA, details=TxRequestDetailsType(request_index=None, tx_hash=unhexlify('d5f65ee80147b4bcc70b75e4bbf2d7382021b871bd8867ef8fa525ef50864882')), serialized=None),
             TxAck(tx=ptx1),
@@ -72,11 +73,11 @@ class TestSignTxFeeThreshold(unittest.TestCase):
             TxAck(tx=TransactionType(bin_outputs=[pout1])),
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
-            signing.UiConfirmOutput(out1, coin_bitcoin),
+            helpers.UiConfirmOutput(out1, coin_bitcoin),
             True,
-            signing.UiConfirmFeeOverThreshold(100000, coin_bitcoin),
+            helpers.UiConfirmFeeOverThreshold(100000, coin_bitcoin),
             True,
-            signing.UiConfirmTotal(290000 + 100000, 100000, coin_bitcoin),
+            helpers.UiConfirmTotal(290000 + 100000, 100000, coin_bitcoin),
             True,
             TxRequest(request_type=TXINPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
         ]
@@ -84,9 +85,10 @@ class TestSignTxFeeThreshold(unittest.TestCase):
         seed = bip39.seed('alcohol woman abuse must during monitor noble actual mixed trade anger aisle', '')
         root = bip32.from_seed(seed, 'secp256k1')
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain([[coin_bitcoin.curve_name]], [root])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
 
     def test_under_threshold(self):
         coin_bitcoin = coins.by_name('Bitcoin')
@@ -127,7 +129,7 @@ class TestSignTxFeeThreshold(unittest.TestCase):
 
             TxRequest(request_type=TXINPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None)),
             TxAck(tx=TransactionType(inputs=[inp1])),
-            signing.UiConfirmForeignAddress(address_n=inp1.address_n),
+            helpers.UiConfirmForeignAddress(address_n=inp1.address_n),
             True,
             TxRequest(request_type=TXMETA, details=TxRequestDetailsType(request_index=None, tx_hash=unhexlify('d5f65ee80147b4bcc70b75e4bbf2d7382021b871bd8867ef8fa525ef50864882')), serialized=None),
             TxAck(tx=ptx1),
@@ -139,9 +141,9 @@ class TestSignTxFeeThreshold(unittest.TestCase):
             TxAck(tx=TransactionType(bin_outputs=[pout1])),
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
-            signing.UiConfirmOutput(out1, coin_bitcoin),
+            helpers.UiConfirmOutput(out1, coin_bitcoin),
             True,
-            signing.UiConfirmTotal(300000 + 90000, 90000, coin_bitcoin),
+            helpers.UiConfirmTotal(300000 + 90000, 90000, coin_bitcoin),
             True,
             TxRequest(request_type=TXINPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
         ]
@@ -149,19 +151,10 @@ class TestSignTxFeeThreshold(unittest.TestCase):
         seed = bip39.seed('alcohol woman abuse must during monitor noble actual mixed trade anger aisle', '')
         root = bip32.from_seed(seed, 'secp256k1')
 
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain([[coin_bitcoin.curve_name]], [root])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
-
-    def assertEqualEx(self, a, b):
-        # hack to avoid adding __eq__ to signing.Ui* classes
-        if ((isinstance(a, signing.UiConfirmOutput) and isinstance(b, signing.UiConfirmOutput)) or
-                (isinstance(a, signing.UiConfirmTotal) and isinstance(b, signing.UiConfirmTotal)) or
-                (isinstance(a, signing.UiConfirmForeignAddress) and isinstance(b, signing.UiConfirmForeignAddress)) or
-                (isinstance(a, signing.UiConfirmFeeOverThreshold) and isinstance(b, signing.UiConfirmFeeOverThreshold))):
-            return self.assertEqual(a.__dict__, b.__dict__)
-        else:
-            return self.assertEqual(a, b)
+            self.assertEqual(signer.send(request), response)
 
 
 if __name__ == '__main__':
diff --git a/tests/test_apps.wallet.signtx.py b/tests/test_apps.wallet.signtx.py
index 1c1869aba3..a7819d4ba5 100644
--- a/tests/test_apps.wallet.signtx.py
+++ b/tests/test_apps.wallet.signtx.py
@@ -15,7 +15,8 @@ from trezor.messages.TxRequestSerializedType import TxRequestSerializedType
 from trezor.messages import OutputScriptType
 
 from apps.common import coins
-from apps.wallet.sign_tx import signing
+from apps.common.seed import Keychain
+from apps.wallet.sign_tx import helpers, signing
 
 
 class TestSignTx(unittest.TestCase):
@@ -61,7 +62,7 @@ class TestSignTx(unittest.TestCase):
 
             TxRequest(request_type=TXINPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None)),
             TxAck(tx=TransactionType(inputs=[inp1])),
-            signing.UiConfirmForeignAddress(address_n=inp1.address_n),
+            helpers.UiConfirmForeignAddress(address_n=inp1.address_n),
             True,
             TxRequest(request_type=TXMETA, details=TxRequestDetailsType(request_index=None, tx_hash=unhexlify('d5f65ee80147b4bcc70b75e4bbf2d7382021b871bd8867ef8fa525ef50864882')), serialized=None),
             TxAck(tx=ptx1),
@@ -73,9 +74,9 @@ class TestSignTx(unittest.TestCase):
             TxAck(tx=TransactionType(bin_outputs=[pout1])),
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
-            signing.UiConfirmOutput(out1, coin_bitcoin),
+            helpers.UiConfirmOutput(out1, coin_bitcoin),
             True,
-            signing.UiConfirmTotal(380000 + 10000, 10000, coin_bitcoin),
+            helpers.UiConfirmTotal(380000 + 10000, 10000, coin_bitcoin),
             True,
             # ButtonRequest(code=ButtonRequest_ConfirmOutput),
             # ButtonRequest(code=ButtonRequest_SignTx),
@@ -96,26 +97,16 @@ class TestSignTx(unittest.TestCase):
         ]
 
         seed = bip39.seed('alcohol woman abuse must during monitor noble actual mixed trade anger aisle', '')
-        root = bip32.from_seed(seed, 'secp256k1')
-
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin_bitcoin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
 
         for request, response in chunks(messages, 2):
             res = signer.send(request)
-            self.assertEqualEx(res, response)
+            self.assertEqual(res, response)
 
         with self.assertRaises(StopIteration):
             signer.send(None)
 
-    def assertEqualEx(self, a, b):
-        # hack to avoid adding __eq__ to signing.Ui* classes
-        if ((isinstance(a, signing.UiConfirmOutput) and isinstance(b, signing.UiConfirmOutput)) or
-                (isinstance(a, signing.UiConfirmForeignAddress) and isinstance(b, signing.UiConfirmForeignAddress)) or
-                (isinstance(a, signing.UiConfirmTotal) and isinstance(b, signing.UiConfirmTotal))):
-            return self.assertEqual(a.__dict__, b.__dict__)
-        else:
-            return self.assertEqual(a, b)
-
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/test_apps.wallet.signtx_grs.py b/tests/test_apps.wallet.signtx_grs.py
index e74d900088..ae33831d3e 100644
--- a/tests/test_apps.wallet.signtx_grs.py
+++ b/tests/test_apps.wallet.signtx_grs.py
@@ -1,7 +1,7 @@
 from common import *
 
 from trezor.utils import chunks
-from trezor.crypto import bip32, bip39
+from trezor.crypto import bip39
 from trezor.messages.SignTx import SignTx
 from trezor.messages.TxInputType import TxInputType
 from trezor.messages.TxOutputType import TxOutputType
@@ -15,7 +15,8 @@ from trezor.messages.TxRequestSerializedType import TxRequestSerializedType
 from trezor.messages import OutputScriptType
 
 from apps.common import coins
-from apps.wallet.sign_tx import signing
+from apps.common.seed import Keychain
+from apps.wallet.sign_tx import helpers, signing
 
 
 class TestSignTx_GRS(unittest.TestCase):
@@ -62,9 +63,9 @@ class TestSignTx_GRS(unittest.TestCase):
             TxAck(tx=TransactionType(bin_outputs=[pout1])),
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
-            signing.UiConfirmOutput(out1, coin),
+            helpers.UiConfirmOutput(out1, coin),
             True,
-            signing.UiConfirmTotal(210016, 192, coin),
+            helpers.UiConfirmTotal(210016, 192, coin),
             True,
             # ButtonRequest(code=ButtonRequest_ConfirmOutput),
             # ButtonRequest(code=ButtonRequest_SignTx),
@@ -85,22 +86,13 @@ class TestSignTx_GRS(unittest.TestCase):
         ]
 
         seed = bip39.seed(' '.join(['all'] * 12), '')
-        root = bip32.from_seed(seed, coin.curve_name)
-
-        signer = signing.sign_tx(tx, root)
+        keychain = Keychain(seed, [[coin.curve_name]])
+        signer = signing.sign_tx(tx, keychain)
         for request, response in chunks(messages, 2):
-            self.assertEqualEx(signer.send(request), response)
+            self.assertEqual(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
-    def assertEqualEx(self, a, b):
-        # hack to avoid adding __eq__ to signing.Ui* classes
-        if ((isinstance(a, signing.UiConfirmOutput) and isinstance(b, signing.UiConfirmOutput)) or
-                (isinstance(a, signing.UiConfirmTotal) and isinstance(b, signing.UiConfirmTotal))):
-            return self.assertEqual(a.__dict__, b.__dict__)
-        else:
-            return self.assertEqual(a, b)
-
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/test_apps.wallet.txweight.py b/tests/test_apps.wallet.txweight.py
index 84e92018dd..becd67ac29 100644
--- a/tests/test_apps.wallet.txweight.py
+++ b/tests/test_apps.wallet.txweight.py
@@ -5,7 +5,7 @@ from trezor.messages import OutputScriptType
 from trezor.crypto import bip32, bip39
 
 from apps.common import coins
-from apps.wallet.sign_tx.tx_weight_calculator import *
+from apps.wallet.sign_tx.tx_weight import *
 from apps.wallet.sign_tx import signing
 
 
diff --git a/vendor/trezor-common b/vendor/trezor-common
index 71528b5260..8906ebf92c 160000
--- a/vendor/trezor-common
+++ b/vendor/trezor-common
@@ -1 +1 @@
-Subproject commit 71528b526020b5c6a95261b07336cff5d68ea66e
+Subproject commit 8906ebf92cf754554f231d4341976c2cf5da9a22