test_f_aws_encryption_sdk_client.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.
"""Functional test suite for aws_encryption_sdk.kms_thick_client"""
import io

import attr
import botocore.client
import cryptography.exceptions
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import padding
from mock import MagicMock
import pytest

import aws_encryption_sdk
from aws_encryption_sdk import KMSMasterKeyProvider
from aws_encryption_sdk.caches import build_decryption_materials_cache_key, build_encryption_materials_cache_key
from aws_encryption_sdk.exceptions import CustomMaximumValueExceeded
from aws_encryption_sdk.identifiers import Algorithm, EncryptionKeyType, WrappingAlgorithm
from aws_encryption_sdk.internal.crypto.wrapping_keys import WrappingKey
from aws_encryption_sdk.internal.formatting.encryption_context import serialize_encryption_context
from aws_encryption_sdk.key_providers.base import MasterKeyProviderConfig
from aws_encryption_sdk.key_providers.raw import RawMasterKeyProvider
from aws_encryption_sdk.materials_managers import DecryptionMaterialsRequest, EncryptionMaterialsRequest

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

VALUES = {
    'frame_lengths': (  # Assuming 1280 byte plaintext:
        0,  # Non-framed
        128,  # Many frames
        1280,  # One exactly full frame, empty final frame
        2048  # One partial, final, frame
    ),
    'data_keys': {
        16: {
            'plaintext': b'v\x84\xc1\x13\x9c\xa8\xaa\xaa\xf3\x07*k8\xa2\xb5]',
            'encrypted': (
                b'\x01\x01\x01\x00x\x8b\xc6\xfd\x91\xc7\xd5\xdc+S\x15n\xd9P\x99n\x1d\xb2\xdd\x15\xeaW\xc3\x13k2\xf6'
                b'\x02\xd0\x0f\x85\xec\x9e\x00\x00\x00n0l\x06\t*\x86H\x86\xf7\r\x01\x07\x06\xa0_0]\x02\x01\x000X\x06'
                b'\t*\x86H\x86\xf7\r\x01\x07\x010\x1e\x06\t`\x86H\x01e\x03\x04\x01.0\x11\x04\x0c\xe9\xd2\x15M8\xfa\xf5'
                b'Z\xc5\xd5l\xf8\x02\x01\x10\x80+\xf7\x1f]\xfc\xbc\xb7\xff\xed|\x81\x99)<x\x18, \x9f\x11\xac\xaa\xd3?q'
                b'$\xf6\xd9\x85\xfcp\xb6z\x88\x8d\xa4\x9e\xe4U\xe6\xe7}W\xcf'
            )
        },
        24: {
            'plaintext': b":\xa7!\xe5\xe8j(u\xb8'\xb2\x1eX`k\x11Ak\x06\x80\xc8\x8c\x83D",
            'encrypted': (
                b'\x01\x01\x01\x00x\x8b\xc6\xfd\x91\xc7\xd5\xdc+S\x15n\xd9P\x99n\x1d\xb2\xdd\x15\xeaW\xc3\x13k2\xf6'
                b'\x02\xd0\x0f\x85\xec\x9e\x00\x00\x00v0t\x06\t*\x86H\x86\xf7\r\x01\x07\x06\xa0g0e\x02\x01\x000`\x06'
                b'\t*\x86H\x86\xf7\r\x01\x07\x010\x1e\x06\t`\x86H\x01e\x03\x04\x01.0\x11\x04\x0cQLG\x10\xe9\x99\x06'
                b'\x1e*\xc3\xc8K\x02\x01\x10\x803\xfa\x83\xad\xe8\\@\x06F\xcd\x01/\x82w\xe8,C\xb7\xdev$\xec66\xa7h\x1d'
                b'c\xb5\xd3\xda\x18\xff\x96$\xf5\xaf\x7f\xc6c\x01\xeb\x85R\xc0\xa7\xcd\xbf\xaf\xb3|\xfe'
            )
        },
        32: {
            'plaintext': (
                b'uW\x05\x10\x0fg\x81\xbc\xec\x97\xb3o\xe2\xc7\xd0\r,\x85N\x9f\x8c\x9b\x92&\xfe\xa4\xae\xd5\xf5\x9b'
                b'\xc7e'
            ),
            'encrypted': (
                b'\x01\x01\x01\x00x\x8b\xc6\xfd\x91\xc7\xd5\xdc+S\x15n\xd9P\x99n\x1d\xb2\xdd\x15\xeaW\xc3\x13k2\xf6'
                b'\x02\xd0\x0f\x85\xec\x9e\x00\x00\x00~0|\x06\t*\x86H\x86\xf7\r\x01\x07\x06\xa0o0m\x02\x01\x000h\x06'
                b'\t*\x86H\x86\xf7\r\x01\x07\x010\x1e\x06\t`\x86H\x01e\x03\x04\x01.0\x11\x04\x0c\xbc\xaf\x0cf^\xf8\xbb'
                b'\xa5\x80-B\xc2\x02\x01\x10\x80;mT\xc2V\x8eN\xa5b\xf2@7_\xa6n\x94\xe6i\xdegM\xe8E\xa6\xb9-H\xf0\x8cBp'
                b'\xc7R\xbb\x04\x8f\xf1+\xc5\x94u-\xf9[\xb9\xf0N*\x9f=:\xda\x9b\xdd\xdd\x08\xe4\x1b\x00('
            )
        }
    },
    'plaintext_128': (
        b'\xa3\xf6\xbc\x89\x95\x15(\xc8}\\\x8d=zu^{JA\xc1\xe9\xf0&m\xe6TD\x03'
        b'\x165F\x85\xae\x96\xd9~ \xa6\x13\x88\xf8\xdb\xc9\x0c\xd8\xd8\xd4\xe0'
        b'\x02\xe9\xdb+\xd4l\xeaq\xf6\xba.cg\xda\xe4V\xd9\x9a\x96\xe8\xf4:\xf5'
        b'\xfd\xd7\xa6\xfa\xd1\x85\xa7o\xf5\x94\xbcE\x14L\xa1\x87\xd9T\xa6\x95'
        b'eZVv\xfe[\xeeJ$a<9\x1f\x97\xe1\xd6\x9dQc\x8b7n\x0f\x1e\xbd\xf5\xba'
        b'\x0e\xae|%\xd8L]\xa2\xa2\x08\x1f'
    ),
    'encryption_context': {
        'key_a': 'value_a',
        'key_b': 'value_b',
        'key_c': 'value_c'
    },
    'arn': b'arn:aws:kms:us-east-1:3333333333333:key/33333333-3333-3333-3333-333333333333',
    'provided': {
        'key': b'\x90\x86Z\x95\x96l\'\xa7\x00yA\x9a\x1a"\xa9\x8e',
        'ciphertext': (
            b'\x01\x80\x00\x14\xe7\xc7\x81\xcfo\x04\xb9\xd3\xbe\xa5\xe5\t,\xb8\x8f\xeb\x00'
            b'\n\x00\x01\x00\x02aa\x00\x02aa\x00\x01\x00\x07aws-kms\x00Karn:aws:kms:us-wes'
            b't-2:249645522726:key/d1720f4e-953b-44bb-b9dd-fc8b9d0baa5f\x00\xbc\n \xf5\x9b'
            b'\x99\x8cX\xa8U\xa9\xbbF\x00\xcf\xd2\xaf+\xd90\xfe\xf3\r\x0e\xdb\x1c\xaf\xf9'
            b'\xfa\x7f\x17\xe8\xb2\xda\xc2\x12\x97\x01\x01\x01\x01\x00x\xf5\x9b\x99\x8cX'
            b'\xa8U\xa9\xbbF\x00\xcf\xd2\xaf+\xd90\xfe\xf3\r\x0e\xdb\x1c\xaf\xf9\xfa\x7f'
            b'\x17\xe8\xb2\xda\xc2\x00\x00\x00n0l\x06\t*\x86H\x86\xf7\r\x01\x07\x06\xa0_0]'
            b'\x02\x01\x000X\x06\t*\x86H\x86\xf7\r\x01\x07\x010\x1e\x06\t`\x86H\x01e\x03\x04'
            b'\x01.0\x11\x04\x0c\x88^o\xd5|\xf2rj`\x06\x80(\x02\x01\x10\x80+\x04\x1cb0\xaf\xff'
            b'V^\x01\x94\xc2\xb1\x7fQ\x02\xde\xd6@\x875\xe9%f\x1c\xb0IS\xc7\xacx\x14\xb2\xea'
            b'\xf6\x80\xfc2\xeb\x99x\xc9\x88Q\x01\x00\x00\x00\x00\x0c\x00\x00\x00\x00\x19m!'
            b'\x15FG\xeeG\x8b\xb2\x03w\xe6\xa6\xfbm}My\x07\xef\xac*\x82\x98\xb6\x84FF\x94%\x8f'
            b'\x97\xed3 \x12\x06\x16\xcf\x00\x00\x00\x00\x00\x00\x00\x1a\x82\xe2$\xb5\xbd\x8c'
            b'\xb4\xcf\xdeF\xc5=$\xea\xdeJ\xe6{\xb7&\x83p9|d\xf8,\xa0\xa3\xa0 \xb3d>\x9f \x05t'
            b'\xa9\x7f\x9f\xed'
        ),
        'plaintext': b"Hello, I'm Java KMS client"
    },
    'raw': {
        b'sym1': {EncryptionKeyType.SYMMETRIC: b'12345678901234567890123456789012'},
        b'asym1': {
            EncryptionKeyType.PRIVATE: (
                b'-----BEGIN RSA PRIVATE KEY-----\n'
                b'MIIEowIBAAKCAQEAo8uCyhiO4JUGZV+rtNq5DBA9Lm4xkw5kTA3v6EPybs8bVXL2\n'
                b'ZE6jkbo+xT4Jg/bKzUpnp1fE+T1ruGPtsPdoEmhY/P64LDNIs3sRq5U4QV9IETU1\n'
                b'vIcbNNkgGhRjV8J87YNY0tV0H7tuWuZRpqnS+gjV6V9lUMkbvjMCc5IBqQc3heut\n'
                b'/+fH4JwpGlGxOVXI8QAapnSy1XpCr3+PT29kydVJnIMuAoFrurojRpOQbOuVvhtA\n'
                b'gARhst1Ji4nfROGYkj6eZhvkz2Bkud4/+3lGvVU5LO1vD8oY7WoGtpin3h50VcWe\n'
                b'aBT4kejx4s9/G9C4R24lTH09J9HO2UUsuCqZYQIDAQABAoIBAQCfC90bCk+qaWqF\n'
                b'gymC+qOWwCn4bM28gswHQb1D5r6AtKBRD8mKywVvWs7azguFVV3Fi8sspkBA2FBC\n'
                b'At5p6ULoJOTL/TauzLl6djVJTCMM701WUDm2r+ZOIctXJ5bzP4n5Q4I7b0NMEL7u\n'
                b'ixib4elYGr5D1vrVQAKtZHCr8gmkqyx8Mz7wkJepzBP9EeVzETCHsmiQDd5WYlO1\n'
                b'C2IQYgw6MJzgM4entJ0V/GPytkodblGY95ORVK7ZhyNtda+r5BZ6/jeMW+hA3VoK\n'
                b'tHSWjHt06ueVCCieZIATmYzBNt+zEz5UA2l7ksg3eWfVORJQS7a6Ef4VvbJLM9Ca\n'
                b'm1kdsjelAoGBANKgvRf39i3bSuvm5VoyJuqinSb/23IH3Zo7XOZ5G164vh49E9Cq\n'
                b'dOXXVxox74ppj/kbGUoOk+AvaB48zzfzNvac0a7lRHExykPH2kVrI/NwH/1OcT/x\n'
                b'2e2DnFYocXcb4gbdZQ+m6X3zkxOYcONRzPVW1uMrFTWHcJveMUm4PGx7AoGBAMcU\n'
                b'IRvrT6ye5se0s27gHnPweV+3xjsNtXZcK82N7duXyHmNjxrwOAv0SOhUmTkRXArM\n'
                b'6aN5D8vyZBSWma2TgUKwpQYFTI+4Sp7sdkkyojGAEixJ+c5TZJNxZFrUe0FwAoic\n'
                b'c2kb7ntaiEj5G+qHvykJJro5hy6uLnjiMVbAiJDTAoGAKb67241EmHAXGEwp9sdr\n'
                b'2SMjnIAnQSF39UKAthkYqJxa6elXDQtLoeYdGE7/V+J2K3wIdhoPiuY6b4vD0iX9\n'
                b'JcGM+WntN7YTjX2FsC588JmvbWfnoDHR7HYiPR1E58N597xXdFOzgUgORVr4PMWQ\n'
                b'pqtwaZO3X2WZlvrhr+e46hMCgYBfdIdrm6jYXFjL6RkgUNZJQUTxYGzsY+ZemlNm\n'
                b'fGdQo7a8kePMRuKY2MkcnXPaqTg49YgRmjq4z8CtHokRcWjJUWnPOTs8rmEZUshk\n'
                b'0KJ0mbQdCFt/Uv0mtXgpFTkEZ3DPkDTGcV4oR4CRfOCl0/EU/A5VvL/U4i/mRo7h\n'
                b'ye+xgQKBgD58b+9z+PR5LAJm1tZHIwb4tnyczP28PzwknxFd2qylR4ZNgvAUqGtU\n'
                b'xvpUDpzMioz6zUH9YV43YNtt+5Xnzkqj+u9Mr27/H2v9XPwORGfwQ5XPwRJz/2oC\n'
                b'EnPmP1SZoY9lXKUpQXHXSpDZ2rE2Klt3RHMUMHt8Zpy36E8Vwx8o\n'
                b'-----END RSA PRIVATE KEY-----\n'
            ),
            EncryptionKeyType.PUBLIC: (
                b'-----BEGIN PUBLIC KEY-----\n'
                b'MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAo8uCyhiO4JUGZV+rtNq5\n'
                b'DBA9Lm4xkw5kTA3v6EPybs8bVXL2ZE6jkbo+xT4Jg/bKzUpnp1fE+T1ruGPtsPdo\n'
                b'EmhY/P64LDNIs3sRq5U4QV9IETU1vIcbNNkgGhRjV8J87YNY0tV0H7tuWuZRpqnS\n'
                b'+gjV6V9lUMkbvjMCc5IBqQc3heut/+fH4JwpGlGxOVXI8QAapnSy1XpCr3+PT29k\n'
                b'ydVJnIMuAoFrurojRpOQbOuVvhtAgARhst1Ji4nfROGYkj6eZhvkz2Bkud4/+3lG\n'
                b'vVU5LO1vD8oY7WoGtpin3h50VcWeaBT4kejx4s9/G9C4R24lTH09J9HO2UUsuCqZ\n'
                b'YQIDAQAB\n'
                b'-----END PUBLIC KEY-----\n'
            )
        }
    }
}


###########
# Helpers #
###########


@attr.s(hash=False)
class FakeRawMasterKeyProviderConfig(MasterKeyProviderConfig):
    wrapping_algorithm = attr.ib()
    encryption_key_type = attr.ib()


class FakeRawMasterKeyProvider(RawMasterKeyProvider):
    provider_id = 'raw'
    _config_class = FakeRawMasterKeyProviderConfig

    def _get_raw_key(self, key_id):
        wrapping_key = VALUES['raw'][key_id][self.config.encryption_key_type]
        if key_id == b'sym1':
            wrapping_key = wrapping_key[:self.config.wrapping_algorithm.algorithm.data_key_len]
        return WrappingKey(
            wrapping_algorithm=self.config.wrapping_algorithm,
            wrapping_key=wrapping_key,
            wrapping_key_type=self.config.encryption_key_type
        )


def _mgf1_sha256_supported():
    wk = serialization.load_pem_private_key(
        data=VALUES['raw'][b'asym1'][EncryptionKeyType.PRIVATE],
        password=None,
        backend=default_backend()
    )
    try:
        wk.public_key().encrypt(
            plaintext=b'aosdjfoiajfoiaj;foijae;rogijaerg',
            padding=padding.OAEP(
                mgf=padding.MGF1(hashes.SHA256()),
                algorithm=hashes.SHA256(),
                label=None
            )
        )
    except cryptography.exceptions.UnsupportedAlgorithm:
        return False
    return True


def fake_kms_client(keysize=32):
    mock_kms_client = MagicMock(__class__=botocore.client.BaseClient)
    mock_kms_client.generate_data_key.return_value = {
        'Plaintext': VALUES['data_keys'][keysize]['plaintext'],
        'CiphertextBlob': VALUES['data_keys'][keysize]['encrypted'],
        'KeyId': VALUES['arn']
    }
    mock_kms_client.encrypt.return_value = {
        'CiphertextBlob': VALUES['data_keys'][keysize]['encrypted'],
        'KeyId': VALUES['arn']
    }
    mock_kms_client.decrypt.return_value = {
        'Plaintext': VALUES['data_keys'][keysize]['plaintext'],
        'KeyId': VALUES['arn']
    }
    return mock_kms_client


def fake_kms_key_provider(keysize=32):
    mock_kms_key_provider = KMSMasterKeyProvider()
    mock_kms_key_provider._regional_clients['us-east-1'] = fake_kms_client(keysize)
    mock_kms_key_provider.add_master_key(VALUES['arn'])
    return mock_kms_key_provider


def build_fake_raw_key_provider(wrapping_algorithm, encryption_key_type):
    key_info = {
        EncryptionKeyType.SYMMETRIC: b'sym1',
        EncryptionKeyType.PRIVATE: b'asym1',
        EncryptionKeyType.PUBLIC: b'asym1'
    }
    raw_key_provider = FakeRawMasterKeyProvider(
        wrapping_algorithm=wrapping_algorithm,
        encryption_key_type=encryption_key_type
    )
    raw_key_provider.add_master_key(key_info[encryption_key_type])
    return raw_key_provider

#########
# Tests #
#########


def test_no_infinite_encryption_cycle_on_empty_source():
    """This catches a race condition where when calling encrypt with
        an empty byte string, encrypt would enter an infinite loop.
        If this test does not hang, the race condition is not present.
    """
    aws_encryption_sdk.encrypt(
        source=b'',
        key_provider=fake_kms_key_provider()
    )


def test_encrypt_load_header():
    """Test that StreamEncryptor can extract header without reading plaintext."""
    # Using a non-signed algorithm to simplify header size calculation
    algorithm = aws_encryption_sdk.Algorithm.AES_256_GCM_IV12_TAG16_HKDF_SHA256
    key_provider = fake_kms_key_provider(algorithm.kdf_input_len)
    header_length = len(serialize_encryption_context(VALUES['encryption_context']))
    header_length += 34
    header_length += algorithm.iv_len
    header_length += algorithm.auth_len
    header_length += 6 + 7 + len(VALUES['arn']) + len(VALUES['data_keys'][algorithm.kdf_input_len]['encrypted'])
    with aws_encryption_sdk.stream(
        mode='e',
        source=VALUES['plaintext_128'],
        key_provider=key_provider,
        encryption_context=VALUES['encryption_context'],
        algorithm=algorithm,
        frame_length=1024
    ) as encryptor:
        encryptor_header = encryptor.header
    # Ensure that only the header has been written into the output buffer
    assert len(encryptor.output_buffer) == header_length
    assert encryptor_header.encryption_context == VALUES['encryption_context']


def test_encrypt_decrypt_header_only():
    """Test that StreamDecryptor can extract header without reading ciphertext."""
    ciphertext, encryptor_header = aws_encryption_sdk.encrypt(
        source=VALUES['plaintext_128'],
        key_provider=fake_kms_key_provider(),
        encryption_context=VALUES['encryption_context']
    )
    with aws_encryption_sdk.stream(
        mode='d',
        source=ciphertext,
        key_provider=fake_kms_key_provider()
    ) as decryptor:
        decryptor_header = decryptor.header
    assert decryptor.output_buffer == b''
    assert all(
        pair in decryptor_header.encryption_context.items()
        for pair in encryptor_header.encryption_context.items()
    )


@pytest.mark.parametrize('frame_length, algorithm, encryption_context', [
    [frame_length, algorithm_suite, encryption_context]
    for frame_length in VALUES['frame_lengths']
    for algorithm_suite in Algorithm
    for encryption_context in [{}, VALUES['encryption_context']]
])
def test_encrypt_ciphertext_message(frame_length, algorithm, encryption_context):
    with aws_encryption_sdk.stream(
        mode='e',
        source=VALUES['plaintext_128'] * 10,
        key_provider=fake_kms_key_provider(algorithm.kdf_input_len),
        encryption_context=encryption_context,
        algorithm=algorithm,
        frame_length=frame_length
    ) as encryptor:
        results_length = encryptor.ciphertext_length()
        ciphertext = encryptor.read()

    assert len(ciphertext) == results_length


@pytest.mark.parametrize('wrapping_algorithm, encryption_key_type, decryption_key_type', (
    (WrappingAlgorithm.AES_256_GCM_IV12_TAG16_NO_PADDING, EncryptionKeyType.SYMMETRIC, EncryptionKeyType.SYMMETRIC),
    (WrappingAlgorithm.RSA_PKCS1, EncryptionKeyType.PRIVATE, EncryptionKeyType.PRIVATE),
    (WrappingAlgorithm.RSA_PKCS1, EncryptionKeyType.PUBLIC, EncryptionKeyType.PRIVATE),
    (WrappingAlgorithm.RSA_OAEP_SHA1_MGF1, EncryptionKeyType.PRIVATE, EncryptionKeyType.PRIVATE),
    (WrappingAlgorithm.RSA_OAEP_SHA1_MGF1, EncryptionKeyType.PUBLIC, EncryptionKeyType.PRIVATE)
))
def test_encryption_cycle_raw_mkp(wrapping_algorithm, encryption_key_type, decryption_key_type):
    encrypting_key_provider = build_fake_raw_key_provider(wrapping_algorithm, encryption_key_type)
    decrypting_key_provider = build_fake_raw_key_provider(wrapping_algorithm, decryption_key_type)
    ciphertext, _ = aws_encryption_sdk.encrypt(
        source=VALUES['plaintext_128'],
        key_provider=encrypting_key_provider,
        encryption_context=VALUES['encryption_context'],
        frame_length=0
    )
    plaintext, _ = aws_encryption_sdk.decrypt(
        source=ciphertext,
        key_provider=decrypting_key_provider
    )
    assert plaintext == VALUES['plaintext_128']


@pytest.mark.skipif(
    not _mgf1_sha256_supported(),
    reason='MGF1-SHA256 not supported by this backend: OpenSSL required v1.0.2+'
)
@pytest.mark.parametrize('wrapping_algorithm, encryption_key_type, decryption_key_type', (
    (WrappingAlgorithm.RSA_OAEP_SHA256_MGF1, EncryptionKeyType.PRIVATE, EncryptionKeyType.PRIVATE),
    (WrappingAlgorithm.RSA_OAEP_SHA256_MGF1, EncryptionKeyType.PUBLIC, EncryptionKeyType.PRIVATE)
))
def test_encryption_cycle_raw_mkp_openssl_102_plus(wrapping_algorithm, encryption_key_type, decryption_key_type):
    encrypting_key_provider = build_fake_raw_key_provider(wrapping_algorithm, encryption_key_type)
    decrypting_key_provider = build_fake_raw_key_provider(wrapping_algorithm, decryption_key_type)
    ciphertext, _ = aws_encryption_sdk.encrypt(
        source=VALUES['plaintext_128'],
        key_provider=encrypting_key_provider,
        encryption_context=VALUES['encryption_context'],
        frame_length=0
    )
    plaintext, _ = aws_encryption_sdk.decrypt(
        source=ciphertext,
        key_provider=decrypting_key_provider
    )
    assert plaintext == VALUES['plaintext_128']


@pytest.mark.parametrize('frame_length, algorithm, encryption_context', [
    [frame_length, algorithm_suite, encryption_context]
    for frame_length in VALUES['frame_lengths']
    for algorithm_suite in Algorithm
    for encryption_context in [{}, VALUES['encryption_context']]
])
def test_encryption_cycle_oneshot_kms(frame_length, algorithm, encryption_context):
    key_provider = fake_kms_key_provider(algorithm.kdf_input_len)

    ciphertext, _ = aws_encryption_sdk.encrypt(
        source=VALUES['plaintext_128'] * 10,
        key_provider=key_provider,
        frame_length=frame_length,
        algorithm=algorithm,
        encryption_context=encryption_context
    )

    plaintext, _ = aws_encryption_sdk.decrypt(
        source=ciphertext,
        key_provider=key_provider
    )

    assert plaintext == VALUES['plaintext_128'] * 10


@pytest.mark.parametrize('frame_length, algorithm, encryption_context', [
    [frame_length, algorithm_suite, encryption_context]
    for frame_length in VALUES['frame_lengths']
    for algorithm_suite in Algorithm
    for encryption_context in [{}, VALUES['encryption_context']]
])
def test_encryption_cycle_stream_kms(frame_length, algorithm, encryption_context):
    key_provider = fake_kms_key_provider(algorithm.kdf_input_len)

    ciphertext = bytearray()
    with aws_encryption_sdk.stream(
        mode='e',
        source=VALUES['plaintext_128'] * 10,
        key_provider=key_provider,
        frame_length=frame_length,
        algorithm=algorithm,
        encryption_context=encryption_context
    ) as encryptor:
        for chunk in encryptor:
            ciphertext.extend(chunk)
    ciphertext = bytes(ciphertext)

    plaintext = bytearray()
    with aws_encryption_sdk.stream(
        mode='d',
        source=io.BytesIO(ciphertext),
        key_provider=key_provider
    ) as decryptor:
        for chunk in decryptor:
            plaintext.extend(chunk)
    plaintext = bytes(plaintext)

    assert ciphertext != plaintext
    assert plaintext == VALUES['plaintext_128'] * 10
    assert encryptor.header.encryption_context == decryptor.header.encryption_context


def test_decrypt_legacy_provided_message():
    """Tests backwards compatiblity against some legacy provided ciphertext."""
    region = 'us-west-2'
    key_info = 'arn:aws:kms:us-west-2:249645522726:key/d1720f4e-953b-44bb-b9dd-fc8b9d0baa5f'
    mock_kms_client = fake_kms_client()
    mock_kms_client.decrypt.return_value = {
        'Plaintext': VALUES['provided']['key']
    }
    mock_kms_key_provider = fake_kms_key_provider()
    mock_kms_key_provider._regional_clients[region] = mock_kms_client
    mock_kms_key_provider.add_master_key(key_info)
    plaintext, _ = aws_encryption_sdk.decrypt(
        source=VALUES['provided']['ciphertext'],
        key_provider=mock_kms_key_provider
    )
    assert plaintext == VALUES['provided']['plaintext']


def test_encryption_cycle_with_caching():
    algorithm = Algorithm.AES_256_GCM_IV12_TAG16_HKDF_SHA384_ECDSA_P384
    frame_length = 1024
    key_provider = fake_kms_key_provider(algorithm.kdf_input_len)
    cache = aws_encryption_sdk.LocalCryptoMaterialsCache(capacity=10)
    ccmm = aws_encryption_sdk.CachingCryptoMaterialsManager(
        master_key_provider=key_provider,
        cache=cache,
        max_age=3600.0,
        max_messages_encrypted=5
    )
    encrypt_kwargs = dict(
        source=VALUES['plaintext_128'],
        materials_manager=ccmm,
        encryption_context=VALUES['encryption_context'],
        frame_length=frame_length,
        algorithm=algorithm
    )
    encrypt_cache_key = build_encryption_materials_cache_key(
        partition=ccmm.partition_name,
        request=EncryptionMaterialsRequest(
            encryption_context=VALUES['encryption_context'],
            frame_length=frame_length,
            algorithm=algorithm,
            plaintext_length=len(VALUES['plaintext_128'])
        )
    )
    ciphertext, header = aws_encryption_sdk.encrypt(**encrypt_kwargs)
    decrypt_cache_key = build_decryption_materials_cache_key(
        partition=ccmm.partition_name,
        request=DecryptionMaterialsRequest(
            algorithm=algorithm,
            encrypted_data_keys=header.encrypted_data_keys,
            encryption_context=header.encryption_context
        )
    )

    assert len(cache._cache) == 1
    assert cache._cache[encrypt_cache_key].messages_encrypted == 1
    assert cache._cache[encrypt_cache_key].bytes_encrypted == 128

    _, _ = aws_encryption_sdk.decrypt(source=ciphertext, materials_manager=ccmm)

    assert len(cache._cache) == 2
    assert decrypt_cache_key in cache._cache

    _, _ = aws_encryption_sdk.encrypt(**encrypt_kwargs)
    _, _ = aws_encryption_sdk.encrypt(**encrypt_kwargs)
    _, _ = aws_encryption_sdk.encrypt(**encrypt_kwargs)

    assert len(cache._cache) == 2
    assert cache._cache[encrypt_cache_key].messages_encrypted == 4
    assert cache._cache[encrypt_cache_key].bytes_encrypted == 512

    _, _ = aws_encryption_sdk.encrypt(**encrypt_kwargs)
    _, _ = aws_encryption_sdk.encrypt(**encrypt_kwargs)
    _, _ = aws_encryption_sdk.encrypt(**encrypt_kwargs)

    assert len(cache._cache) == 2
    assert cache._cache[encrypt_cache_key].messages_encrypted == 2
    assert cache._cache[encrypt_cache_key].bytes_encrypted == 256


def test_encrypt_source_length_enforcement():
    key_provider = fake_kms_key_provider()
    cmm = aws_encryption_sdk.DefaultCryptoMaterialsManager(key_provider)
    with pytest.raises(CustomMaximumValueExceeded) as excinfo:
        aws_encryption_sdk.encrypt(
            source=VALUES['plaintext_128'],
            materials_manager=cmm,
            source_length=int(len(VALUES['plaintext_128']) / 2)
        )

    excinfo.match(r'Bytes encrypted has exceeded stated source length estimate:*')


def test_encrypt_source_length_enforcement_legacy_support():
    # To maintain legacy compatibility, source length is only enforced
    # if a crypto materials manager is provided; not if a master key
    # provider is provided.
    key_provider = fake_kms_key_provider()
    aws_encryption_sdk.encrypt(
        source=VALUES['plaintext_128'],
        key_provider=key_provider,
        source_length=int(len(VALUES['plaintext_128']) / 2)
    )


class NoSeekBytesIO(io.BytesIO):
    """``io.BytesIO`` that blocks ``seek()`` and ``tell()``."""

    def seekable(self):
        return False

    def seek(self, offset, whence=0):
        raise NotImplementedError('seek is blocked')

    def tell(self):
        raise NotImplementedError('tell is blocked')


def test_stream_encryptor_no_seek_input():
    """Test that StreamEncryptor can handle an input stream that is not seekable."""
    key_provider = fake_kms_key_provider()
    plaintext = NoSeekBytesIO(VALUES['plaintext_128'])
    ciphertext = io.BytesIO()
    with aws_encryption_sdk.StreamEncryptor(
        source=plaintext,
        key_provider=key_provider,
        encryption_context=VALUES['encryption_context']
    ) as encryptor:
        for chunk in encryptor:
            ciphertext.write(chunk)
    decrypted, _header = aws_encryption_sdk.decrypt(
        source=ciphertext.getvalue(),
        key_provider=key_provider
    )
    assert decrypted == VALUES['plaintext_128']


def test_stream_decryptor_no_seek_input():
    """Test that StreamDecryptor can handle an input stream that is not seekable."""
    key_provider = fake_kms_key_provider()
    ciphertext, _header = aws_encryption_sdk.encrypt(
        source=VALUES['plaintext_128'],
        key_provider=key_provider,
        encryption_context=VALUES['encryption_context']
    )
    ciphertext_no_seek = NoSeekBytesIO(ciphertext)
    decrypted = io.BytesIO()
    with aws_encryption_sdk.StreamDecryptor(
        source=ciphertext_no_seek,
        key_provider=key_provider
    ) as decryptor:
        for chunk in decryptor:
            decrypted.write(chunk)
    assert decrypted.getvalue() == VALUES['plaintext_128']


def test_encrypt_oneshot_no_seek_input():
    """Test that encrypt can handle an input stream that is not seekable."""
    key_provider = fake_kms_key_provider()
    plaintext = NoSeekBytesIO(VALUES['plaintext_128'])
    ciphertext, _header = aws_encryption_sdk.encrypt(
        source=plaintext,
        key_provider=key_provider,
        encryption_context=VALUES['encryption_context']
    )
    decrypted, _header = aws_encryption_sdk.decrypt(
        source=ciphertext,
        key_provider=key_provider
    )
    assert decrypted == VALUES['plaintext_128']


def test_decrypt_oneshot_no_seek_input():
    """Test that decrypt can handle an input stream that is not seekable."""
    key_provider = fake_kms_key_provider()
    ciphertext, _header = aws_encryption_sdk.encrypt(
        source=VALUES['plaintext_128'],
        key_provider=key_provider,
        encryption_context=VALUES['encryption_context']
    )
    ciphertext_no_seek = NoSeekBytesIO(ciphertext)
    decrypted, _header = aws_encryption_sdk.decrypt(
        source=ciphertext_no_seek,
        key_provider=key_provider
    )
    assert decrypted == VALUES['plaintext_128']