trezor-firmware/src/apps/common/signverify.py

from ubinascii import hexlify

from trezor.crypto.hashlib import sha256
from trezor.utils 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)
    ret = h.get_digest()
    if coin.sign_hash_double:
        ret = sha256(ret).digest()
    return ret


def split_message(message):
    try:
        m = bytes(message).decode()
        words = m.split(" ")
    except UnicodeError:
        m = hexlify(message)
        words = [m]
    return words