trezor-firmware/core/src/apps/cardano/helpers/bech32.py

from trezor.crypto import bech32

HRP_SEPARATOR = "1"

HRP_ADDRESS = "addr"
HRP_TESTNET_ADDRESS = "addr_test"
HRP_REWARD_ADDRESS = "stake"
HRP_TESTNET_REWARD_ADDRESS = "stake_test"


def encode(hrp: str, data: bytes) -> str:
    converted_bits = bech32.convertbits(data, 8, 5)
    if converted_bits is None:
        raise ValueError
    return bech32.bech32_encode(hrp, converted_bits)


def decode_unsafe(bech: str) -> bytes:
    hrp = get_hrp(bech)
    return decode(hrp, bech)


def get_hrp(bech: str) -> str:
    return bech.rsplit(HRP_SEPARATOR, 1)[0]


def decode(hrp: str, bech: str) -> bytes:
    decoded_hrp, data = bech32.bech32_decode(bech, 130)
    if data is None:
        raise ValueError
    if decoded_hrp != hrp:
        raise ValueError

    decoded = bech32.convertbits(data, 5, 8, False)
    if decoded is None:
        raise ValueError

    return bytes(decoded)