def get_crypto_ecdsa_pubkey_from_bitcoin_hex(bitcoin_hex_key):
"""
Given a bitcoin hex string key returns the corresponding cryptography ECDSA key object
:param bitcoin_hex_key: the h
:return: cryptography ECDSA key object
"""
bin_ecdsa_public_key = extract_bin_ecdsa_pubkey(bitcoin_hex_key)
numbers = EllipticCurvePublicNumbers.from_encoded_point(ec.SECP256K1(), b'\x04' + bin_ecdsa_public_key)
return numbers.public_key(backend=default_backend())
def validate_message(message):
"""Validates the entire message using the signature found in the message footer."""
encoded_point = base64.b64decode(
message.header.encryption_context['aws-crypto-public-key'])
public_numbers = EllipticCurvePublicNumbers.from_encoded_point(
ec.SECP384R1(), encoded_point)
public_key = public_numbers.public_key(default_backend())
verifier = public_key.verifier(message.footer.signature,
ec.ECDSA(hashes.SHA384()))
verifier.update(message.serialize_authenticated_fields())
verifier.verify()
logging.info("Message integrity verified.")
def _load_uncompressed_verification_key_from_encryption_context(
self, algorithm, encryption_context):
# pylint: disable=no-self-use
"""Loads the verification key from an uncompressed elliptic curve point.
:param algorithm: Algorithm for which to generate signing key
:type algorithm: aws_encryption_sdk.identifiers.Algorithm
:param dict encryption_context: Encryption context from request
:returns: Raw verification key
:rtype: bytes
"""
# If we are at this point, DefaultCryptoMaterialsManager has already confirmed that:
# a) a key should be loaded,
# b) the key field is present in the encryption context, and
# c) the elliptic curve in the encryption context is not compressed
# This means that we can safely skip the safety checks that we know have already been done.
uncompressed_point = base64.b64decode(
encryption_context[ENCODED_SIGNER_KEY])
public_key = EllipticCurvePublicNumbers.from_encoded_point(
curve=algorithm.signing_algorithm_info(),
data=uncompressed_point).public_key(default_backend())
return public_key.public_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PublicFormat.SubjectPublicKeyInfo)
def deserialize_pub_key(public_key_ser):
numbers = EllipticCurvePublicNumbers.from_encoded_point(
CURVE(), public_key_ser)
return numbers.public_key(backend=BACKEND)