def from_seed(cls, ledger, seed):
# This hard-coded message string seems to be coin-independent...
hmac = hmac_sha512(b'Bitcoin seed', seed)
privkey, chain_code = hmac[:32], hmac[32:]
return cls(ledger, privkey, chain_code, 0, 0)
def _hmac_sha512(self, msg):
""" Use SHA-512 to provide an HMAC, returned as a pair of 32-byte objects. """
hmac = hmac_sha512(self.chain_code, msg)
return hmac[:32], hmac[32:]
def is_new_seed(seed, prefix):
seed = normalize_text(seed)
seed_hash = hexlify(hmac_sha512(b"Seed version", seed.encode('utf8')))
return seed_hash.startswith(prefix)