edu.tamu.tcat.crypto.bouncycastle.SymmetricCipherBuilderImpl.java Source code

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Here is the source code for edu.tamu.tcat.crypto.bouncycastle.SymmetricCipherBuilderImpl.java

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/*
 * Copyright 2014 Texas A&M Engineering Experiment Station
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License 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 edu.tamu.tcat.crypto.bouncycastle;

import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.BufferedBlockCipher;
import org.bouncycastle.crypto.engines.AESEngine;
import org.bouncycastle.crypto.modes.AEADBlockCipher;
import org.bouncycastle.crypto.modes.CBCBlockCipher;
import org.bouncycastle.crypto.modes.GCMBlockCipher;
import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithIV;

import edu.tamu.tcat.crypto.AEADSymmetricCipher;
import edu.tamu.tcat.crypto.CipherException;
import edu.tamu.tcat.crypto.SymmetricCipher;
import edu.tamu.tcat.crypto.SymmetricCipherBuilder;
import edu.tamu.tcat.crypto.bouncycastle.internal.BouncyCastleAEADCipher;
import edu.tamu.tcat.crypto.bouncycastle.internal.BouncyCastleBlockCipher;

/**
 * @since 1.1
 */
public class SymmetricCipherBuilderImpl implements SymmetricCipherBuilder {
    @Override
    public SymmetricCipher buildCipher(Cipher cipher, Mode mode, boolean encryption, byte[] key, byte[] iv)
            throws CipherException {
        ParametersWithIV cipherParameters = new ParametersWithIV(new KeyParameter(key), iv);
        BlockCipher underlyingCipher = null;
        switch (cipher) {
        case AES128:
        case AES192:
        case AES256:
            underlyingCipher = new AESEngine();
            break;
        }
        BlockCipher blockCipher = null;
        switch (mode) {
        case CBC:
            blockCipher = new CBCBlockCipher(underlyingCipher);
            break;
        case GCM:
            throw new CipherException("GCM mode is authenticating encryption; use buildAEADCipher instead");
        }
        BufferedBlockCipher bufferedBlockCipher = new PaddedBufferedBlockCipher(blockCipher);
        bufferedBlockCipher.init(encryption, cipherParameters);

        return new BouncyCastleBlockCipher(bufferedBlockCipher);
    }

    @Override
    public AEADSymmetricCipher buildAEADCipher(Cipher cipher, Mode mode, boolean encryption, byte[] key, byte[] iv)
            throws CipherException {
        ParametersWithIV cipherParameters = new ParametersWithIV(new KeyParameter(key), iv);
        BlockCipher underlyingCipher = null;
        int macSize = 0;
        switch (cipher) {
        case AES128:
        case AES192:
        case AES256:
            underlyingCipher = new AESEngine();
            break;
        }
        AEADBlockCipher aeadCipher = null;
        switch (mode) {
        case CBC:
            throw new CipherException(mode + " is not an authenticating encryption mode; use buildCipher instead");
        case GCM:
            aeadCipher = new GCMBlockCipher(underlyingCipher);
            macSize = underlyingCipher.getBlockSize();
            break;
        }
        aeadCipher.init(encryption, cipherParameters);

        return new BouncyCastleAEADCipher(aeadCipher, macSize, encryption);
    }
}