FrameDecryptionHandlerTest.java

/*
 * Copyright 2016 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.
 */

package com.amazonaws.encryptionsdk.internal;

import static org.junit.Assert.assertTrue;

import java.nio.ByteBuffer;
import java.security.SecureRandom;

import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import com.amazonaws.encryptionsdk.TestUtils;
import com.amazonaws.encryptionsdk.exception.BadCiphertextException;
import org.junit.Before;
import org.junit.Test;

import com.amazonaws.encryptionsdk.AwsCrypto;
import com.amazonaws.encryptionsdk.CryptoAlgorithm;
import com.amazonaws.encryptionsdk.exception.AwsCryptoException;

public class FrameDecryptionHandlerTest {
    private static final SecureRandom RND = new SecureRandom();
    private final CryptoAlgorithm cryptoAlgorithm_ = AwsCrypto.getDefaultCryptoAlgorithm();
    private final byte[] messageId_ = new byte[Constants.MESSAGE_ID_LEN];
    private final byte nonceLen_ = cryptoAlgorithm_.getNonceLen();
    private final byte[] dataKeyBytes_ = new byte[cryptoAlgorithm_.getKeyLength()];
    private final SecretKey dataKey_ = new SecretKeySpec(dataKeyBytes_, "AES");
    private final int frameSize_ = AwsCrypto.getDefaultFrameSize();

    private final FrameDecryptionHandler frameDecryptionHandler_ = new FrameDecryptionHandler(
            dataKey_,
            nonceLen_,
            cryptoAlgorithm_,
            messageId_,
            frameSize_);

    @Before
    public void setup() {
        RND.nextBytes(messageId_);
        RND.nextBytes(dataKeyBytes_);
    }

    @Test
    public void estimateOutputSize() {
        final int inLen = 1;
        final int outSize = frameDecryptionHandler_.estimateOutputSize(inLen);

        // the estimated output size must at least be equal to inLen.
        assertTrue(outSize >= inLen);
    }

    @Test(expected = AwsCryptoException.class)
    public void decryptMaxContentLength() {
        // Create input of size 1 byte: 1 byte of the sequence number,
        // Only 1 byte of the sequence number is provided because this
        // forces the frame decryption handler to buffer that 1 byte while
        // waiting for the remaining bytes of the sequence number. We do this so
        // we can specify an input of max value and the total bytes to parse
        // will become max value + 1.
        final byte[] in = new byte[1];
        final byte[] out = new byte[1];

        frameDecryptionHandler_.processBytes(in, 0, in.length, out, 0);
        frameDecryptionHandler_.processBytes(in, 0, Integer.MAX_VALUE, out, 0);
    }

    @Test(expected = BadCiphertextException.class)
    public void finalFrameLengthTooLarge() {

        final ByteBuffer byteBuffer = ByteBuffer.allocate(25);
        byteBuffer.put(TestUtils.unsignedBytesToSignedBytes(
                new int[] {255, 255, 255, 255, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}));
        byteBuffer.putInt(AwsCrypto.getDefaultFrameSize() + 1);

        final byte[] in = byteBuffer.array();
        final byte[] out = new byte[in.length];

        frameDecryptionHandler_.processBytes(in, 0, in.length, out, 0);
    }
}