java AES256 GCM

public static int MacBitSize = 128;

public static String encrypt(String PlainText, byte[] key, byte[] iv) {
    String sR = "";
    try {
        byte[] plainBytes = PlainText.getBytes("UTF-8");

        GCMBlockCipher cipher = new GCMBlockCipher(new AESFastEngine());
        AEADParameters parameters =
                new AEADParameters(new KeyParameter(key), MacBitSize, iv, null);
        cipher.init(true, parameters);

        byte[] encryptedBytes = new byte[cipher.getOutputSize(plainBytes.length)];
        int retLen = cipher.processBytes(plainBytes, 0, plainBytes.length, encryptedBytes, 0);
        cipher.doFinal(encryptedBytes, retLen);
        sR = java.util.Base64.getEncoder().encodeToString(encryptedBytes);
    } catch (UnsupportedEncodingException | IllegalArgumentException |
            IllegalStateException | DataLengthException | InvalidCipherTextException ex) {
        System.out.println(ex.getMessage());
    }

    return sR;
}


public static String decrypt(String EncryptedText, byte[] key, byte[] iv) {
    String sR = "";
    try {
        byte[] encryptedBytes = java.util.Base64.getDecoder().decode(EncryptedText);

        GCMBlockCipher cipher = new GCMBlockCipher(new AESFastEngine());
        AEADParameters parameters =
                new AEADParameters(new KeyParameter(key), MacBitSize, iv, null);

        cipher.init(false, parameters);
        byte[] plainBytes = new byte[cipher.getOutputSize(encryptedBytes.length)];
        int retLen = cipher.processBytes
                (encryptedBytes, 0, encryptedBytes.length, plainBytes, 0);
        cipher.doFinal(plainBytes, retLen);
        sR = new String(plainBytes, Charset.forName("UTF-8"));
    } catch (IllegalArgumentException | IllegalStateException |
            DataLengthException | InvalidCipherTextException ex) {
        System.out.println(ex.getMessage());
    }

    return sR;
}

public static void main(String[] args) throws IOException {

　　String Key = "abcdefqwertyu";
　　String IV = "abcdef";

　　String encryptedText = encrypt(plainText,Key.getBytes(),IV.getBytes());

　　String decryptedText = decrypt(encryptedText, Key.getBytes(),IV.getBytes());

}


一：添加jar包 bcprov-jdk15.jar

二：

　　jdk低版本不支持256长度的秘钥加密，需确认一下配置
　　进入jdk 的 \jre\lib\security目录 看是否有limited和unlimited文件夹。
　　1 没有这个两个文件夹
　　下载local_policy.jar 和 US_export_policy.jar替换当前的。下载路径http://pan.baidu.com/s/1dDBY9xB
　　2.有这个两个文件夹
　　在security文件夹找到java.security文件并打开， 确保 crypto.policy=unlimited 这行配置没被屏蔽。如屏蔽了，去掉签名的#