com.intel.chimera.codec.JceAesCtrCryptoCodec.java Source code

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Here is the source code for com.intel.chimera.codec.JceAesCtrCryptoCodec.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.intel.chimera.codec;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.security.GeneralSecurityException;
import java.security.SecureRandom;
import java.util.Properties;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.google.common.base.Preconditions;
import com.intel.chimera.utils.Utils;

/**
 * Implement the AES-CTR crypto codec using JCE provider.
 */
public class JceAesCtrCryptoCodec extends AesCtrCryptoCodec {
    private static final Log LOG = LogFactory.getLog(JceAesCtrCryptoCodec.class.getName());

    private String provider;
    private SecureRandom random;

    public JceAesCtrCryptoCodec(Properties props) {
        provider = Utils.getJCEProvider(props);
        final String secureRandomAlg = Utils.getSecureRandomAlg(props);
        try {
            random = (provider != null) ? SecureRandom.getInstance(secureRandomAlg, provider)
                    : SecureRandom.getInstance(secureRandomAlg);
        } catch (GeneralSecurityException e) {
            LOG.warn(e.getMessage());
            random = new SecureRandom();
        }
    }

    @Override
    public Encryptor createEncryptor() throws GeneralSecurityException {
        return new JceAesCtrCipher(Cipher.ENCRYPT_MODE, provider);
    }

    @Override
    public Decryptor createDecryptor() throws GeneralSecurityException {
        return new JceAesCtrCipher(Cipher.DECRYPT_MODE, provider);
    }

    @Override
    public void generateSecureRandom(byte[] bytes) {
        random.nextBytes(bytes);
    }

    private static class JceAesCtrCipher implements Encryptor, Decryptor {
        private final Cipher cipher;
        private final int mode;
        private boolean contextReset = false;

        public JceAesCtrCipher(int mode, String provider) throws GeneralSecurityException {
            this.mode = mode;
            if (provider == null || provider.isEmpty()) {
                cipher = Cipher.getInstance(SUITE.getName());
            } else {
                cipher = Cipher.getInstance(SUITE.getName(), provider);
            }
        }

        @Override
        public void init(byte[] key, byte[] iv) throws IOException {
            Preconditions.checkNotNull(key);
            Preconditions.checkNotNull(iv);
            contextReset = false;
            try {
                cipher.init(mode, new SecretKeySpec(key, "AES"), new IvParameterSpec(iv));
            } catch (Exception e) {
                throw new IOException(e);
            }
        }

        /**
         * AES-CTR will consume all of the input data. It requires enough space in 
         * the destination buffer to encrypt entire input buffer.
         */
        @Override
        public void encrypt(ByteBuffer inBuffer, ByteBuffer outBuffer) throws IOException {
            process(inBuffer, outBuffer);
        }

        /**
         * AES-CTR will consume all of the input data. It requires enough space in
         * the destination buffer to decrypt entire input buffer.
         */
        @Override
        public void decrypt(ByteBuffer inBuffer, ByteBuffer outBuffer) throws IOException {
            process(inBuffer, outBuffer);
        }

        @Override
        public boolean isContextReset() {
            return contextReset;
        }

        private void process(ByteBuffer inBuffer, ByteBuffer outBuffer) throws IOException {
            try {
                int inputSize = inBuffer.remaining();
                // Cipher#update will maintain crypto context.
                int n = cipher.update(inBuffer, outBuffer);
                if (n < inputSize) {
                    /**
                     * Typically code will not get here. Cipher#update will consume all 
                     * input data and put result in outBuffer. 
                     * Cipher#doFinal will reset the crypto context.
                     */
                    contextReset = true;
                    cipher.doFinal(inBuffer, outBuffer);
                }
            } catch (Exception e) {
                throw new IOException(e);
            }
        }
    }
}