trezor-firmware/src/apps/wallet/sign_message.py

from trezor import ui
from trezor.crypto.curve import secp256k1
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


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.derive_node(ctx, address_n)
    seckey = node.private_key()

    address = node.address(coin.address_type)
    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)