JAVA实现AES 解密报错Input length must be multiple of 16 when decrypting with padded cipher

加密代码

　

        /**解密
         * @param content  待解密内容
         * @param password 解密密钥
         * @return
         */
        public static byte[] decrypt(byte[] content, String password) {
                try {
                         KeyGenerator kgen = KeyGenerator.getInstance("AES");
                         kgen.init(128, new SecureRandom(password.getBytes()));
                         SecretKey secretKey = kgen.generateKey();
                         byte[] enCodeFormat = secretKey.getEncoded();
                         SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
                         Cipher cipher = Cipher.getInstance("AES");// 创建密码器
                        cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
                        byte[] result = cipher.doFinal(content);
                        return result; // 加密
                } catch (NoSuchAlgorithmException e) {
                        e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                        e.printStackTrace();
                } catch (InvalidKeyException e) {
                        e.printStackTrace();
                } catch (IllegalBlockSizeException e) {
                        e.printStackTrace();
                } catch (BadPaddingException e) {
                        e.printStackTrace();
                }
                return null;
        }

　　

　

解密代码

        /**解密
         * @param content  待解密内容
         * @param password 解密密钥
         * @return
         */
        public static byte[] decrypt(byte[] content, String password) {
                try {
                         KeyGenerator kgen = KeyGenerator.getInstance("AES");
                         kgen.init(128, new SecureRandom(password.getBytes()));
                         SecretKey secretKey = kgen.generateKey();
                         byte[] enCodeFormat = secretKey.getEncoded();
                         SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
                         Cipher cipher = Cipher.getInstance("AES");// 创建密码器
                        cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
                        byte[] result = cipher.doFinal(content);
                        return result; // 加密
                } catch (NoSuchAlgorithmException e) {
                        e.printStackTrace();
                } catch (NoSuchPaddingException e) {
                        e.printStackTrace();
                } catch (InvalidKeyException e) {
                        e.printStackTrace();
                } catch (IllegalBlockSizeException e) {
                        e.printStackTrace();
                } catch (BadPaddingException e) {
                        e.printStackTrace();
                }
                return null;
        }

　　

解密代码

                String content = "test";
                String password = "12345678";
                //加密
                System.out.println("加密前：" + content);
                byte[] encryptResult = encrypt(content, password);
                try {
                        String encryptResultStr = new String(encryptResult,"utf-8");
                        //解密
                        byte[] decryptResult = decrypt(encryptResultStr.getBytes("utf-8"),password);
                        System.out.println("解密后：" + new String(decryptResult));
                } catch (UnsupportedEncodingException e) {
                        e.printStackTrace();
                }

　　

偶尔会报错 抛出异常，

javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher

原因  加密后的byte数组是不能强制转换成字符串的，换言之：字符串和byte数组在这种情况下不是互逆的；要避免这种情况，我们需要做一些修订，可以考虑将二进制数据转换成十六进制表示

解决方案 

二进制转换成16进制

        /**将16进制转换为二进制
         * @param hexStr
         * @return
         */
        public static byte[] parseHexStr2Byte(String hexStr) {
                if (hexStr.length() < 1)
                        return null;
                byte[] result = new byte[hexStr.length()/2];
                for (int i = 0;i< hexStr.length()/2; i++) {
                        int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
                        int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
                        result[i] = (byte) (high * 16 + low);
                }
                return result;
        }

　　

16进制转换为二进制

测试结果，问题解决

                String content = "test";
                String password = "12345678";
                //加密
                System.out.println("加密前：" + content);
                byte[] encryptResult = encrypt(content, password);
                String encryptResultStr = parseByte2HexStr(encryptResult);
                System.out.println("加密后：" + encryptResultStr);
                //解密
                byte[] decryptFrom = parseHexStr2Byte(encryptResultStr);
                byte[] decryptResult = decrypt(decryptFrom,password);
                System.out.println("解密后：" + new String(decryptResult));

　　

测试结果如下：

加密前：test
加密后：73C58BAFE578C59366D8C995CD0B9D6D
解密后：test

文档参考 http://blog.****.net/hbcui1984/article/details/5201247