test_f_crypto_iv.py

# Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
"""Unit test suite for IV generation helper functions."""
import pytest

from aws_encryption_sdk.exceptions import ActionNotAllowedError
from aws_encryption_sdk.internal.crypto.iv import frame_iv, header_auth_iv, non_framed_body_iv
from aws_encryption_sdk.internal.defaults import ALGORITHM, MAX_FRAME_COUNT

pytestmark = [pytest.mark.functional, pytest.mark.local]

VALUES = {
    'ivs': {
        'header_auth': b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
        'non_framed': b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01',
        'frame': [
            {
                'sequence_number': 1,
                'iv': b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01'
            },
            {
                'sequence_number': 10000,
                'iv': b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'\x10"
            },
            {
                'sequence_number': 4294967295,  # 2^32 - 1 :: max frame count
                'iv': b'\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff\xff\xff'
            }
        ]
    }
}


@pytest.mark.parametrize('sequence_number, iv', [
    (entry['sequence_number'], entry['iv'])
    for entry in VALUES['ivs']['frame']
])
def test_framed_iv(sequence_number, iv):
    assert frame_iv(ALGORITHM, sequence_number) == iv


@pytest.mark.parametrize('sequence_number', (-1, 0, MAX_FRAME_COUNT + 1))
def test_framed_iv_invalid_sequence_numbers(sequence_number):
    with pytest.raises(ActionNotAllowedError) as excinfo:
        frame_iv(ALGORITHM, sequence_number)

    excinfo.match(r'Invalid frame sequence number: *')


def test_non_framed_body_iv():
    assert non_framed_body_iv(ALGORITHM) == VALUES['ivs']['non_framed']


def test_header_auth_iv():
    assert header_auth_iv(ALGORITHM) == VALUES['ivs']['header_auth']