extensions.py 文件源码

def _key_identifier_from_public_key(public_key):
    # This is a very slow way to do this.
    serialized = public_key.public_bytes(
        serialization.Encoding.DER,
        serialization.PublicFormat.SubjectPublicKeyInfo
    )
    spki, remaining = decoder.decode(
        serialized, asn1Spec=_SubjectPublicKeyInfo()
    )
    assert not remaining
    # the univ.BitString object is a tuple of bits. We need bytes and
    # pyasn1 really doesn't want to give them to us. To get it we'll
    # build an integer and convert that to bytes.
    bits = 0
    for bit in spki.getComponentByName("subjectPublicKey"):
        bits = bits << 1 | bit

    data = utils.int_to_bytes(bits)
    return hashlib.sha1(data).digest()