com.amazonaws.tvm.AESEncryption.java Source code

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Here is the source code for com.amazonaws.tvm.AESEncryption.java

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/*
 * Copyright 2010-2012 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.tvm;

import java.security.AlgorithmParameters;
import java.security.SecureRandom;

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

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;

public class AESEncryption {

    public static final String ENCRYPTION_ALGORITHM = "AES/CBC/PKCS5Padding";

    public static String wrap(String clearText, String key) throws Exception {
        byte[] iv = getIv();

        byte[] cipherText = encrypt(clearText, key, iv);
        byte[] wrapped = new byte[iv.length + cipherText.length];
        System.arraycopy(iv, 0, wrapped, 0, iv.length);
        System.arraycopy(cipherText, 0, wrapped, 16, cipherText.length);

        return new String(Base64.encodeBase64(wrapped));
    }

    public static byte[] encrypt(String clearText, String key, byte[] iv) throws Exception {
        Cipher cipher = Cipher.getInstance(ENCRYPTION_ALGORITHM);
        AlgorithmParameters params = AlgorithmParameters.getInstance("AES");
        params.init(new IvParameterSpec(iv));
        cipher.init(Cipher.ENCRYPT_MODE, getKey(key), params);
        return cipher.doFinal(clearText.getBytes());
    }

    private static SecretKeySpec getKey(String key) throws Exception {
        return new SecretKeySpec(Hex.decodeHex(key.toCharArray()), "AES");
    }

    private static byte[] getIv() throws Exception {
        byte[] iv = new byte[16];
        new SecureRandom().nextBytes(iv);

        return iv;
    }
}