crypto.py 文件源码

def encrypt_pk(pub_key, plaintext):
    """
    Encrypt plaintext with the RSA public key pub_key, using CryptoHash()
    as the OAEP/MGF1 padding hash.
    plaintext is limited to the size of the RSA key, minus the padding, or a
    few hundred bytes.
    Returns a b64encoded ciphertext string.
    Encryption failures result in an exception being raised.
    """
    try:
        ciphertext = pub_key.encrypt(
            plaintext,
            padding.OAEP(
                mgf=padding.MGF1(algorithm=CryptoHash()),
                algorithm=CryptoHash(),
                label=None
                )
            )
    except UnsupportedAlgorithm as e:
        # a failure to encrypt our own data is a fatal error
        # the most likely cause of this error is an old cryptography library
        # although some newer binary cryptography libraries are linked with
        # old OpenSSL versions, to fix, check 'openssl version' >= 1.0.2, then:
        # pip install -I --no-binary cryptography cryptography
        logging.error("Fatal error: encryption hash {} unsupported, try upgrading to cryptography >= 1.4 compiled with OpenSSL >= 1.0.2. Exception: {}".format(
                          CryptoHash, e))
        # re-raise the exception for the caller to handle
        raise e
    return b64encode(ciphertext)