diff --git a/src/apps/lisk/get_address.py b/src/apps/lisk/get_address.py
index b5228ec2ad..a273289d8b 100644
--- a/src/apps/lisk/get_address.py
+++ b/src/apps/lisk/get_address.py
@@ -1,11 +1,11 @@
+from apps.common import seed
 from apps.wallet.get_address import _show_address, _show_qr
+from trezor.messages.LiskAddress import LiskAddress
+
 from .helpers import LISK_CURVE, get_address_from_public_key
 
 
 async def layout_lisk_get_address(ctx, msg):
-    from trezor.messages.LiskAddress import LiskAddress
-    from ..common import seed
-
     address_n = msg.address_n or ()
 
     node = await seed.derive_node(ctx, address_n, LISK_CURVE)
diff --git a/src/apps/lisk/get_public_key.py b/src/apps/lisk/get_public_key.py
index 6973ac1246..d79ec6fb1e 100644
--- a/src/apps/lisk/get_public_key.py
+++ b/src/apps/lisk/get_public_key.py
@@ -1,11 +1,11 @@
+from apps.common import seed
 from apps.wallet.get_public_key import _show_pubkey
+from trezor.messages.LiskPublicKey import LiskPublicKey
+
 from .helpers import LISK_CURVE
 
 
 async def lisk_get_public_key(ctx, msg):
-    from trezor.messages.LiskPublicKey import LiskPublicKey
-    from ..common import seed
-
     address_n = msg.address_n or ()
 
     node = await seed.derive_node(ctx, address_n, LISK_CURVE)
diff --git a/src/apps/lisk/helpers.py b/src/apps/lisk/helpers.py
index 4371ca2c3c..87aa46aaa5 100644
--- a/src/apps/lisk/helpers.py
+++ b/src/apps/lisk/helpers.py
@@ -1,12 +1,13 @@
+from trezor.crypto.hashlib import sha256
 
 LISK_CURVE = 'ed25519'
 
-def get_address_from_public_key(public_key):
-    from trezor.crypto.hashlib import sha256
 
-    public_key_hash = sha256(public_key).digest()
-    address = int.from_bytes(public_key_hash[:8], 'little')
-    return str(address) + "L"
+def get_address_from_public_key(pubkey):
+    pubkeyhash = sha256(pubkey).digest()
+    address = int.from_bytes(pubkeyhash[:8], 'little')
+    return str(address) + 'L'
+
 
 def get_votes_count(votes):
     plus, minus = 0, 0
@@ -17,6 +18,7 @@ def get_votes_count(votes):
             minus += 1
     return plus, minus
 
+
 def get_vote_tx_text(votes):
     plus, minus = get_votes_count(votes)
     text = []
@@ -26,5 +28,6 @@ def get_vote_tx_text(votes):
         text.append(_text_with_plural('Remove', minus))
     return text
 
+
 def _text_with_plural(txt, value):
     return '%s %s %s' % (txt, value, ('votes' if value != 1 else 'vote'))
diff --git a/src/apps/lisk/layout.py b/src/apps/lisk/layout.py
index 002622e92d..2847a4afd1 100644
--- a/src/apps/lisk/layout.py
+++ b/src/apps/lisk/layout.py
@@ -1,8 +1,10 @@
-from apps.common.confirm import *
+from apps.common.confirm import require_confirm, require_hold_to_confirm
+from apps.wallet.get_public_key import _show_pubkey
 from trezor import ui
-from trezor.utils import chunks
 from trezor.messages import ButtonRequestType
 from trezor.ui.text import Text
+from trezor.utils import chunks
+
 from .helpers import get_vote_tx_text
 
 
@@ -14,6 +16,7 @@ async def require_confirm_tx(ctx, to, value):
                     icon_color=ui.GREEN)
     return await require_confirm(ctx, content, ButtonRequestType.SignTx)
 
+
 async def require_confirm_delegate_registration(ctx, delegate_name):
     content = Text('Confirm transaction', ui.ICON_SEND,
                    'Do you really want to',
@@ -22,26 +25,27 @@ async def require_confirm_delegate_registration(ctx, delegate_name):
                     icon_color=ui.GREEN)
     return await require_confirm(ctx, content, ButtonRequestType.SignTx)
 
+
 async def require_confirm_vote_tx(ctx, votes):
     content = Text('Confirm transaction', ui.ICON_SEND,
                     *get_vote_tx_text(votes),
                     icon_color=ui.GREEN)
-
     return await require_confirm(ctx, content, ButtonRequestType.SignTx)
 
+
 async def require_confirm_public_key(ctx, public_key):
-    from apps.wallet.get_public_key import _show_pubkey
     return await _show_pubkey(ctx, public_key)
 
+
 async def require_confirm_multisig(ctx, multisignature):
     content = Text('Confirm transaction', ui.ICON_SEND,
                     ('Keys group length: %s' % len(multisignature.keys_group)),
                     ('Life time: %s' % multisignature.life_time),
                     ('Min: %s' % multisignature.min),
                     icon_color=ui.GREEN)
-
     return await require_confirm(ctx, content, ButtonRequestType.SignTx)
 
+
 async def require_confirm_fee(ctx, value, fee):
     content = Text('Confirm transaction', ui.ICON_SEND,
                    ui.BOLD, format_amount(value),
@@ -50,8 +54,10 @@ async def require_confirm_fee(ctx, value, fee):
                    icon_color=ui.GREEN)
     await require_hold_to_confirm(ctx, content, ButtonRequestType.ConfirmOutput)
 
+
 def format_amount(value):
     return '%s LSK' % (int(value) / 100000000)
 
+
 def split_address(address):
     return chunks(address, 16)
diff --git a/src/apps/lisk/sign_tx.py b/src/apps/lisk/sign_tx.py
index 9da973cc29..28a0167c72 100644
--- a/src/apps/lisk/sign_tx.py
+++ b/src/apps/lisk/sign_tx.py
@@ -1,112 +1,39 @@
-from trezor import wire, ui
+import ustruct
+from apps.common import seed
+from trezor import wire
+from trezor.crypto.curve import ed25519
+from trezor.crypto.hashlib import sha256
+from trezor.messages import LiskTransactionType
 from trezor.messages.LiskSignedTx import LiskSignedTx
-from trezor.messages.LiskTransactionType import *
-from trezor.messages import FailureType
 from trezor.utils import HashWriter
-from apps.lisk.layout import *
-from ubinascii import unhexlify, hexlify
+
+from . import layout
+from .helpers import LISK_CURVE, get_address_from_public_key
 
 
 async def lisk_sign_tx(ctx, msg):
-    from trezor.crypto.hashlib import sha256
-
     pubkey, seckey = await _get_keys(ctx, msg)
-    transaction = update_raw_tx(msg.transaction, pubkey)
+    transaction = _update_raw_tx(msg.transaction, pubkey)
 
-    # throw ValueError if transaction has not valid structure
     try:
-        await require_confirm_by_type(ctx, transaction)
+        await _require_confirm_by_type(ctx, transaction)
     except AttributeError:
-        raise ValueError(FailureType.DataError, 'The transaction has invalid asset data field')
+        raise wire.DataError('The transaction has invalid asset data field')
 
-    await require_confirm_fee(ctx, transaction.amount, transaction.fee)
+    await layout.require_confirm_fee(ctx, transaction.amount, transaction.fee)
 
-    sha = HashWriter(sha256)
-    transaction_bytes = _get_transaction_bytes(transaction)
+    txbytes = _get_transaction_bytes(transaction)
+    txhash = HashWriter(sha256)
+    for field in txbytes:
+        txhash.extend(field)
+    digest = txhash.get_digest()
 
-    for field in transaction_bytes:
-        sha.extend(field)
-
-    digest = sha.get_digest()
-
-    signature = await get_signature(seckey, digest)
+    signature = ed25519.sign(seckey, digest)
 
     return LiskSignedTx(signature=signature)
 
-async def require_confirm_by_type(ctx, transaction):
-    if transaction.type == Transfer:
-        return await require_confirm_tx(ctx, transaction.recipient_id, transaction.amount)
-    if transaction.type == RegisterDelegate:
-        return await require_confirm_delegate_registration(ctx, transaction.asset.delegate.username)
-    if transaction.type == CastVotes:
-        return await require_confirm_vote_tx(ctx, transaction.asset.votes)
-    if transaction.type == RegisterSecondPassphrase:
-        return await require_confirm_public_key(ctx, transaction.asset.signature.public_key)
-    if transaction.type == RegisterMultisignatureAccount:
-        return await require_confirm_multisig(ctx, transaction.asset.multisignature)
-    raise ValueError(FailureType.DataError, 'Invalid transaction type')
-
-async def get_signature(seckey, digest):
-    from trezor.crypto.curve import ed25519
-    signature = ed25519.sign(seckey, digest)
-
-    return signature
-
-def _get_transaction_bytes(msg):
-    from ustruct import pack
-
-    # Required transaction parameters
-    t_type = pack('<b', msg.type)
-    t_timestamp = pack('<i', msg.timestamp)
-    t_amount = pack('<Q', msg.amount)
-    t_pubkey = msg.sender_public_key
-
-    t_requester_public_key = msg.requester_public_key or b''
-
-    # Value can be empty string
-    if not msg.recipient_id:
-        t_recipient_id = pack('>Q', 0)
-    else:
-        # Lisk use big-endian for recipient_id
-        # string -> int -> bytes
-        t_recipient_id = pack('>Q', int(msg.recipient_id[:-1]))
-
-    t_signature = msg.signature or b''
-
-    t_asset = _get_asset_data_bytes(msg)
-
-    return t_type, t_timestamp, t_pubkey, t_requester_public_key, t_recipient_id, t_amount, t_asset, t_signature
-
-def _get_asset_data_bytes(msg):
-    from ustruct import pack
-
-    if msg.type == Transfer:
-        # Transfer transaction have optional data field
-        if msg.asset.data is not None:
-            return bytes(msg.asset.data, "utf8")
-        else:
-            return b''
-
-    if msg.type == RegisterDelegate:
-        return bytes(msg.asset.delegate.username, "utf8")
-
-    if msg.type == CastVotes:
-        return bytes("".join(msg.asset.votes), "utf8")
-
-    if msg.type == RegisterSecondPassphrase:
-        return msg.asset.signature.public_key
-
-    if msg.type == RegisterMultisignatureAccount:
-        data = b''
-        data += pack('<b', msg.asset.multisignature.min)
-        data += pack('<b', msg.asset.multisignature.life_time)
-        data += bytes("".join(msg.asset.multisignature.keys_group), "utf8")
-        return data
 
 async def _get_keys(ctx, msg):
-    from ..common import seed
-    from .helpers import LISK_CURVE
-
     address_n = msg.address_n or ()
     node = await seed.derive_node(ctx, address_n, LISK_CURVE)
 
@@ -116,13 +43,89 @@ async def _get_keys(ctx, msg):
 
     return pubkey, seckey
 
-def update_raw_tx(transaction, pubkey):
-    from .helpers import get_address_from_public_key
 
+def _update_raw_tx(transaction, pubkey):
     transaction.sender_public_key = pubkey
 
-    # For this type of transactions, recipientId should be equal transaction creator address.
-    if transaction.type == CastVotes:
+    # For CastVotes transactions, recipientId should be equal to transaction
+    # creator address.
+    if transaction.type == LiskTransactionType.CastVotes:
         transaction.recipient_id = get_address_from_public_key(pubkey)
 
     return transaction
+
+
+async def _require_confirm_by_type(ctx, transaction):
+
+    if transaction.type == LiskTransactionType.Transfer:
+        return await layout.require_confirm_tx(
+            ctx, transaction.recipient_id, transaction.amount)
+
+    if transaction.type == LiskTransactionType.RegisterDelegate:
+        return await layout.require_confirm_delegate_registration(
+            ctx, transaction.asset.delegate.username)
+
+    if transaction.type == LiskTransactionType.CastVotes:
+        return await layout.require_confirm_vote_tx(
+            ctx, transaction.asset.votes)
+
+    if transaction.type == LiskTransactionType.RegisterSecondPassphrase:
+        return await layout.require_confirm_public_key(
+            ctx, transaction.asset.signature.public_key)
+
+    if transaction.type == LiskTransactionType.RegisterMultisignatureAccount:
+        return await layout.require_confirm_multisig(
+            ctx, transaction.asset.multisignature)
+
+    raise wire.DataError('Invalid transaction type')
+
+
+def _get_transaction_bytes(tx):
+
+    # Required transaction parameters
+    t_type = ustruct.pack('<b', tx.type)
+    t_timestamp = ustruct.pack('<i', tx.timestamp)
+    t_sender_public_key = tx.sender_public_key
+    t_requester_public_key = tx.requester_public_key or b''
+
+    if not tx.recipient_id:
+        # Value can be empty string
+        t_recipient_id = ustruct.pack('>Q', 0)
+    else:
+        # Lisk uses big-endian for recipient_id, string -> int -> bytes
+        t_recipient_id = ustruct.pack('>Q', int(tx.recipient_id[:-1]))
+
+    t_amount = ustruct.pack('<Q', tx.amount)
+    t_asset = _get_asset_data_bytes(tx)
+    t_signature = tx.signature or b''
+
+    return (t_type, t_timestamp, t_sender_public_key, t_requester_public_key,
+            t_recipient_id, t_amount, t_asset, t_signature)
+
+
+def _get_asset_data_bytes(msg):
+
+    if msg.type == LiskTransactionType.Transfer:
+        # Transfer transaction have optional data field
+        if msg.asset.data is not None:
+            return bytes(msg.asset.data, 'utf8')
+        else:
+            return b''
+
+    if msg.type == LiskTransactionType.RegisterDelegate:
+        return bytes(msg.asset.delegate.username, 'utf8')
+
+    if msg.type == LiskTransactionType.CastVotes:
+        return bytes(''.join(msg.asset.votes), 'utf8')
+
+    if msg.type == LiskTransactionType.RegisterSecondPassphrase:
+        return msg.asset.signature.public_key
+
+    if msg.type == LiskTransactionType.RegisterMultisignatureAccount:
+        data = b''
+        data += ustruct.pack('<b', msg.asset.multisignature.min)
+        data += ustruct.pack('<b', msg.asset.multisignature.life_time)
+        data += bytes(''.join(msg.asset.multisignature.keys_group), 'utf8')
+        return data
+
+    raise wire.DataError('Invalid transaction type')