def serialize_encrypted_data_key()

in src/aws_encryption_sdk/internal/formatting/serialize.py [0:0]

• 27 lines of code
• 6 McCabe index (conditional complexity)

def serialize_encrypted_data_key(encrypted_data_key):
    """Serializes an encrypted data key.

    .. versionadded:: 1.3.0

    :param encrypted_data_key: Encrypted data key to serialize
    :type encrypted_data_key: aws_encryption_sdk.structures.EncryptedDataKey
    :returns: Serialized encrypted data key
    :rtype: bytes
    """
    encrypted_data_key_format = (
        ">"  # big endian
        "H"  # key provider ID length
        "{provider_id_len}s"  # key provider ID
        "H"  # key info length
        "{provider_info_len}s"  # key info
        "H"  # encrypted data key length
        "{enc_data_key_len}s"  # encrypted data key
    )
    # ESDK-Python <4.0.1 incorrectly computed len_key_provider_id_bytes for non-ASCII key provider IDs.
    # len_key_provider_id_bytes was computed as the length of the key provider ID as a string instead of
    #   the length of the key provider ID as UTF-8 bytes.
    # If a non-ASCII key provider ID were supplied, the key provider ID as UTF-8 bytes written to the header
    #   would be truncated, and attempting to decrypt the message would result in a deserialization error.
    # The message can be decrypted by replacing the truncated provider ID with the expected provider ID
    #   in decryption code.
    # Contact AWS for any questions about this approach.
    # ESDK-Python >=4.0.1 corrects the serialization logic and writes the correct length and expected bytes
    #   to the message header.
    key_provider_id_bytes = to_bytes(encrypted_data_key.key_provider.provider_id)
    len_key_provider_id_bytes = len(key_provider_id_bytes)
    key_info_bytes = to_bytes(encrypted_data_key.key_provider.key_info)
    len_key_info_bytes = len(key_info_bytes)
    return struct.pack(
        encrypted_data_key_format.format(
            provider_id_len=len_key_provider_id_bytes,
            provider_info_len=len_key_info_bytes,
            enc_data_key_len=len(encrypted_data_key.encrypted_data_key),
        ),
        len_key_provider_id_bytes,
        key_provider_id_bytes,
        len_key_info_bytes,
        key_info_bytes,
        len(encrypted_data_key.encrypted_data_key),
        encrypted_data_key.encrypted_data_key,
    )