加密算法--AES

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java实现AES加密算法，随机iv值合入到加密文件中，使得每次加密的内容不一样。
核心代码如下。

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public static final int AES_KEY_SIZE = 256; // in bits
public static final int GCM_NONCE_LENGTH = 12; // in bytes
public static final String CIPHER = "AES";
public static final String AES_GCM_NOPADDING = "AES/GCM/NoPadding";// java 8-u162 以后版本才支持
public static final String AES_GCM_PKCS5PADDING = "AES/GCM/PKCS5Padding";// java 8-u162 以后版本才支持
public static final String AES_CBC_NOPADDING = "AES/CBC/NoPadding";
public static final String AES_CBC_PKCS5PADDING = "AES/CBC/PKCS5Padding";	
/**
 * 生成秘钥的方法
 * 
 * @param encryptPass
 * @return
 */
public static SecretKey getSecreKey(String encryptPass) {
    SecretKey key = null;
    try {
        KeyGenerator keyGen = KeyGenerator.getInstance(CIPHER);
        keyGen.init(AES_KEY_SIZE, new SecureRandom(encryptPass.getBytes(StandardCharsets.UTF_8)));
        key = keyGen.generateKey();
        System.out.println(Base64.getEncoder().encodeToString(key.getEncoded()));
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    }
    return key;
}
/**
 * AES加密
 * 
 * @param content
 * @param encryptPass
 * @return
 */
public static String encrypt(String content, String encryptPass) {
    try {
        Cipher cipher = Cipher.getInstance(AES_GCM_PKCS5PADDING);
        cipher.init(Cipher.ENCRYPT_MODE, getSecreKey(encryptPass));
        byte[] iv = cipher.getIV();
        byte[] encryptData = cipher.doFinal(content.getBytes(StandardCharsets.UTF_8));
        byte[] message = new byte[12 + content.getBytes(StandardCharsets.UTF_8).length + 16];
        System.arraycopy(iv, 0, message, 0, 12);
        System.arraycopy(encryptData, 0, message, 12, encryptData.length);
        return Base64.getEncoder().encodeToString(message);
    } catch (NoSuchAlgorithmException | NoSuchPaddingException | IllegalBlockSizeException | BadPaddingException
        | InvalidKeyException e) {
        e.printStackTrace();
    }
    return null;
}
/**
 * AES解密
 * 
 * @param base64Content
 * @param encryptPass
 * @return
 * @throws IllegalBlockSizeException
 */
public static String decrypt(String base64Content, String encryptPass) throws IllegalBlockSizeException {
    byte[] content = Base64.getDecoder().decode(base64Content);
    if (content.length < 12 + 16) {
        throw new IllegalBlockSizeException();
    }
    GCMParameterSpec spec = new GCMParameterSpec(GCM_TAG_LENGTH * 8, content, 0, 12);
    try {
        Cipher cipher = Cipher.getInstance(AES_GCM_PKCS5PADDING);
        cipher.init(Cipher.DECRYPT_MODE, getSecreKey(encryptPass), spec);
        byte[] decryptData = cipher.doFinal(content, 12, content.length - 12);
        return new String(decryptData);
    } catch (NoSuchAlgorithmException | NoSuchPaddingException | IllegalBlockSizeException | BadPaddingException
        | InvalidKeyException | InvalidAlgorithmParameterException e) {
        e.printStackTrace();
    }
    return null;
}

注意：GCM模式java 8-u162 版本以后才支持，以前的版本不能使用该加密模式。
不建议使用ECB模式，ECB模式现阶段存在破解的可能。