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

from trezor import wire
from trezor.crypto import bip32, bip39

from apps.common import cache, storage
from apps.common.request_passphrase import protect_by_passphrase

_DEFAULT_CURVE = "secp256k1"


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


async def _get_cached_seed(ctx: wire.Context) -> bytes:
    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 = 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()


def derive_node_without_passphrase(
    path: list, curve_name: str = _DEFAULT_CURVE
) -> 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)
    return node


def remove_ed25519_public_key_prefix(pubkey: bytes) -> bytes:
    # 0x01 prefix is not part of the actual public key, hence removed
    return pubkey[1:]