转的JAVA实现AES加密

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JAVA实现AES加密

1. 因子???????上次介绍了《JAVA实现AES加密》，中间提到近些年DES使用越来越少，原因就在于其使用56位密钥，比较容易被破解，近些年来逐渐被AES替代，AES已经变成目前对称加密中最流行算法之一；AES可以使用128、192、和256位密钥，并且用128位分组加密和解密数据。本文就简单介绍如何通过JAVA实现AES加密。2. JAVA实现闲话少许，掠过AES加密原理及算法，关于这些直接搜索专业网站吧，我们直接看JAVA的具体实现。2.1 加密代码有详细解释，不多废话。view plain

1. /**??*?加密?
2. ?*???*?@param?content?需要加密的内容?
3. ?*?@param?password??加密密码??*?@return?
4. ?*/??public?static?byte[]?encrypt(String?content,?String?password)?{??
5. ????????try?{?????????????????????????????KeyGenerator?kgen?=?KeyGenerator.getInstance("AES");??
6. ????????????????kgen.init(128,?new?SecureRandom(password.getBytes()));??????????????????SecretKey?secretKey?=?kgen.generateKey();??
7. ????????????????byte[]?enCodeFormat?=?secretKey.getEncoded();??????????????????SecretKeySpec?key?=?new?SecretKeySpec(enCodeFormat,?"AES");??
8. ????????????????Cipher?cipher?=?Cipher.getInstance("AES");//?创建密码器??????????????????byte[]?byteContent?=?content.getBytes("utf-8");??
9. ????????????????cipher.init(Cipher.ENCRYPT_MODE,?key);//?初始化??????????????????byte[]?result?=?cipher.doFinal(byteContent);??
10. ????????????????return?result;?//?加密??????????}?catch?(NoSuchAlgorithmException?e)?{??
11. ????????????????e.printStackTrace();??????????}?catch?(NoSuchPaddingException?e)?{??
12. ????????????????e.printStackTrace();??????????}?catch?(InvalidKeyException?e)?{??
13. ????????????????e.printStackTrace();??????????}?catch?(UnsupportedEncodingException?e)?{??
14. ????????????????e.printStackTrace();??????????}?catch?(IllegalBlockSizeException?e)?{??
15. ????????????????e.printStackTrace();??????????}?catch?(BadPaddingException?e)?{??
16. ????????????????e.printStackTrace();??????????}??
17. ????????return?null;??}??

2.2 解密代码有详细注释，不多废话注意：解密的时候要传入byte数组view plain

1. /**解密??*?@param?content??待解密内容?
2. ?*?@param?password?解密密钥??*?@return?
3. ?*/??public?static?byte[]?decrypt(byte[]?content,?String?password)?{??
4. ????????try?{???????????????????KeyGenerator?kgen?=?KeyGenerator.getInstance("AES");??
5. ?????????????????kgen.init(128,?new?SecureRandom(password.getBytes()));???????????????????SecretKey?secretKey?=?kgen.generateKey();??
6. ?????????????????byte[]?enCodeFormat?=?secretKey.getEncoded();???????????????????SecretKeySpec?key?=?new?SecretKeySpec(enCodeFormat,?"AES");??????????????
7. ?????????????????Cipher?cipher?=?Cipher.getInstance("AES");//?创建密码器??????????????????cipher.init(Cipher.DECRYPT_MODE,?key);//?初始化??
8. ????????????????byte[]?result?=?cipher.doFinal(content);??????????????????return?result;?//?加密??
9. ????????}?catch?(NoSuchAlgorithmException?e)?{??????????????????e.printStackTrace();??
10. ????????}?catch?(NoSuchPaddingException?e)?{??????????????????e.printStackTrace();??
11. ????????}?catch?(InvalidKeyException?e)?{??????????????????e.printStackTrace();??
12. ????????}?catch?(IllegalBlockSizeException?e)?{??????????????????e.printStackTrace();??
13. ????????}?catch?(BadPaddingException?e)?{??????????????????e.printStackTrace();??
14. ????????}??????????return?null;??
15. }??

2.3 测试代码view plain

1. String?content?=?"test";??String?password?=?"12345678";??
2. //加密??System.out.println("加密前："?+?content);??
3. byte[]?encryptResult?=?encrypt(content,?password);??//解密??
4. byte[]?decryptResult?=?decrypt(encryptResult,password);??System.out.println("解密后："?+?new?String(decryptResult));??

输出结果如下：加密前：test
解密后：test2.4 容易出错的地方但是如果我们将测试代码修改一下，如下：view plain

1. String?content?=?"test";??String?password?=?"12345678";??
2. //加密??System.out.println("加密前："?+?content);??
3. byte[]?encryptResult?=?encrypt(content,?password);??try?{??
4. ????????String?encryptResultStr?=?new?String(encryptResult,"utf-8");??????????//解密??
5. ????????byte[]?decryptResult?=?decrypt(encryptResultStr.getBytes("utf-8"),password);??????????System.out.println("解密后："?+?new?String(decryptResult));??
6. }?catch?(UnsupportedEncodingException?e)?{??????????e.printStackTrace();??
7. }??

则，系统会报出如下异常：javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher
????????at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
????????at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
????????at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
????????at javax.crypto.Cipher.doFinal(DashoA13*..)这主要是因为加密后的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，主要有如下两个方法：2.4.1将二进制转换成16进制view plain

1. /**将二进制转换成16进制??*?@param?buf?
2. ?*?@return??*/??
3. public?static?String?parseByte2HexStr(byte?buf[])?{??????????StringBuffer?sb?=?new?StringBuffer();??
4. ????????for?(int?i?=?0;?i?<?buf.length;?i++)?{??????????????????String?hex?=?Integer.toHexString(buf[i]?&?0xFF);??
5. ????????????????if?(hex.length()?==?1)?{??????????????????????????hex?=?'0'?+?hex;??
6. ????????????????}??????????????????sb.append(hex.toUpperCase());??
7. ????????}??????????return?sb.toString();??
8. }??

2.4.2 将16进制转换为二进制view plain

1. /**将16进制转换为二进制??*?@param?hexStr?
2. ?*?@return??*/??
3. public?static?byte[]?parseHexStr2Byte(String?hexStr)?{??????????if?(hexStr.length()?<?1)??
4. ????????????????return?null;??????????byte[]?result?=?new?byte[hexStr.length()/2];??
5. ????????for?(int?i?=?0;i<?hexStr.length()/2;?i++)?{??????????????????int?high?=?Integer.parseInt(hexStr.substring(i*2,?i*2+1),?16);??
6. ????????????????int?low?=?Integer.parseInt(hexStr.substring(i*2+1,?i*2+2),?16);??????????????????result[i]?=?(byte)?(high?*?16?+?low);??
7. ????????}??????????return?result;??
8. }??

然后，我们再修订以上测试代码，如下：view plain

1. String?content?=?"test";??String?password?=?"12345678";??
2. //加密??System.out.println("加密前："?+?content);??
3. byte[]?encryptResult?=?encrypt(content,?password);??String?encryptResultStr?=?parseByte2HexStr(encryptResult);??
4. System.out.println("加密后："?+?encryptResultStr);??//解密??
5. byte[]?decryptFrom?=?parseHexStr2Byte(encryptResultStr);??byte[]?decryptResult?=?decrypt(decryptFrom,password);??
6. 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?2.5 另外一种加密方式还有一种加密方式，大家可以参考如下：view plain

1. /**???????*?加密?
2. ??????*???????*?@param?content?需要加密的内容?
3. ??????*?@param?password??加密密码???????*?@return?
4. ??????*/???????public?static?byte[]?encrypt2(String?content,?String?password)?{??
5. ?????????????try?{???????????????????????SecretKeySpec?key?=?new?SecretKeySpec(password.getBytes(),?"AES");??
6. ?????????????????????Cipher?cipher?=?Cipher.getInstance("AES/ECB/NoPadding");???????????????????????byte[]?byteContent?=?content.getBytes("utf-8");??
7. ?????????????????????cipher.init(Cipher.ENCRYPT_MODE,?key);//?初始化???????????????????????byte[]?result?=?cipher.doFinal(byteContent);??
8. ?????????????????????return?result;?//?加密???????????????}?catch?(NoSuchAlgorithmException?e)?{??
9. ?????????????????????e.printStackTrace();???????????????}?catch?(NoSuchPaddingException?e)?{??
10. ?????????????????????e.printStackTrace();???????????????}?catch?(InvalidKeyException?e)?{??
11. ?????????????????????e.printStackTrace();???????????????}?catch?(UnsupportedEncodingException?e)?{??
12. ?????????????????????e.printStackTrace();???????????????}?catch?(IllegalBlockSizeException?e)?{??
13. ?????????????????????e.printStackTrace();???????????????}?catch?(BadPaddingException?e)?{??
14. ?????????????????????e.printStackTrace();???????????????}??
15. ?????????????return?null;???????}??

这种加密方式有两种限制密钥必须是16位的待加密内容的长度必须是16的倍数，如果不是16的倍数，就会出如下异常：javax.crypto.IllegalBlockSizeException: Input length not multiple of 16 bytes
????????at com.sun.crypto.provider.SunJCE_f.a(DashoA13*..)
????????at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
????????at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
????????at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
????????at javax.crypto.Cipher.doFinal(DashoA13*..)要解决如上异常，可以通过补全传入加密内容等方式进行避免。