apps/wallet: sign & verify message layouts

src/apps/common/signverify.py

@@ -1,15 +1,26 @@
+from micropython import const
 from trezor.crypto.hashlib import sha256
-
-from apps.wallet.sign_tx.signing import write_varint
+from trezor.utils import chunks
 from apps.common.hash_writer import HashWriter
+from apps.wallet.sign_tx.signing import write_varint
 
 
 def message_digest(coin, message):
-
     h = HashWriter(sha256)
     write_varint(h, len(coin.signed_message_header))
     h.extend(coin.signed_message_header)
     write_varint(h, len(message))
     h.extend(message)
-
     return sha256(h.get_digest()).digest()
+
+
+def split_message(message):
+    chars_per_line = const(18)
+    message = stringify_message(message)
+    lines = chunks(message, chars_per_line)
+    return lines
+
+
+def stringify_message(message):
+    # TODO: account for invalid UTF-8 sequences
+    return str(message, 'utf-8')

src/apps/wallet/sign_message.py

@@ -1,29 +1,32 @@
 from trezor import ui
-
-
-async def layout_sign_message(ctx, msg):
-    from trezor.messages.MessageSignature import MessageSignature
 from trezor.crypto.curve import secp256k1
-    from ..common import coins
-    from ..common import seed
-    from ..common.signverify import message_digest
+from trezor.messages.MessageSignature import MessageSignature
+from trezor.ui.text import Text
+from apps.common import coins, seed
+from apps.common.confirm import require_confirm
+from apps.common.signverify import message_digest, split_message
 
-    ui.display.clear()
-    ui.display.text(10, 30, 'Signing message',
-                    ui.BOLD, ui.LIGHT_GREEN, ui.BG)
-    ui.display.text(10, 60, msg.message, ui.MONO, ui.FG, ui.BG)
 
+async def sign_message(ctx, msg):
+    message = msg.message
+    address_n = msg.address_n
     coin_name = msg.coin_name or 'Bitcoin'
     coin = coins.by_name(coin_name)
 
+    await confirm_sign_message(ctx, message)
+
     node = await seed.get_root(ctx)
-    node.derive_path(msg.address_n)
-
+    node.derive_path(address_n)
     seckey = node.private_key()
+
     address = node.address(coin.address_type)
-
-    digest = message_digest(coin, msg.message)
-
+    digest = message_digest(coin, message)
     signature = secp256k1.sign(seckey, digest)
 
     return MessageSignature(address=address, signature=signature)
+
+
+async def confirm_sign_message(ctx, message):
+    message = split_message(message)
+    content = Text('Sign message', ui.ICON_CONFIRM, ui.MONO, *message)
+    await require_confirm(ctx, content)

src/apps/wallet/verify_message.py

@@ -1,35 +1,41 @@
-from trezor import ui
-
-
-async def layout_verify_message(ctx, msg):
-    from trezor.messages.Success import Success
+from trezor import ui, wire
+from trezor.crypto import base58
 from trezor.crypto.curve import secp256k1
 from trezor.crypto.hashlib import ripemd160, sha256
-    from trezor.crypto import base58
-    from ..common import address_type
-    from ..common import coins
-    from ..common.signverify import message_digest
+from trezor.messages.FailureType import ProcessError
+from trezor.messages.Success import Success
+from trezor.ui.text import Text
+from apps.common import address_type, coins
+from apps.common.confirm import require_confirm
+from apps.common.signverify import message_digest, split_message
 
+
+async def verify_message(ctx, msg):
+    message = msg.message
+    address = msg.address
+    signature = msg.signature
     coin_name = msg.coin_name or 'Bitcoin'
     coin = coins.by_name(coin_name)
 
-    digest = message_digest(coin, msg.message)
-    pubkey = secp256k1.verify_recover(msg.signature, digest)
+    await confirm_verify_message(ctx, message)
+
+    digest = message_digest(coin, message)
+    pubkey = secp256k1.verify_recover(signature, digest)
 
     if not pubkey:
-        raise ValueError('Invalid signature')
+        raise wire.FailureError(ProcessError, 'Invalid signature')
 
-    raw_address = base58.decode_check(msg.address)
-    at, pkh = address_type.split(coin, raw_address)
+    raw_address = base58.decode_check(address)
+    _, pkh = address_type.split(coin, raw_address)
     pkh2 = ripemd160(sha256(pubkey).digest()).digest()
 
     if pkh != pkh2:
-        raise ValueError('Invalid signature')
-
-    ui.display.clear()
-    ui.display.text(10, 30, 'Verifying message',
-                    ui.BOLD, ui.LIGHT_GREEN, ui.BG)
-    ui.display.text(10, 60, msg.message, ui.MONO, ui.FG, ui.BG)
-    ui.display.text(10, 80, msg.address, ui.MONO, ui.FG, ui.BG)
+        raise wire.FailureError(ProcessError, 'Invalid signature')
 
     return Success(message='Message verified')
+
+
+async def confirm_verify_message(ctx, message):
+    message = split_message(message)
+    content = Text('Verify message', ui.ICON_CONFIRM, ui.MONO, *message)
+    await require_confirm(ctx, content)