原文地址：http://songjianyong.iteye.com/blog/1571029
/**
* AESHelper.java
* cn.com.songjy.test
*
* Function： TODO
*
* ver date author
* ──────────────────────────────────
* 2012-6-29 songjianyong
*
* Copyright (c) 2012, TNT All Rights Reserved.
*/package cn.com.songjy.test;import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;/**
* ClassName:AESHelper
*
* @author songjianyong
* @version 1.0
* @since v1.0
* @Date 2012-6-29 下午2:06:07
*/
public class AESHelper { /**
* @method main
* @param args
* @throws
* @since v1.0
*/ public static void main(String[] args) { String content = "宋建勇";
String password = "12345678";
byte[] encryptResult = encrypt(content, password);//加密
byte[] decryptResult = decrypt(encryptResult,password);//解密
System.out.println("解密后：" + new String(decryptResult)); /*容易出错的地方，请看下面代码*/
System.out.println("***********************************************");
try {
String encryptResultStr = new String(encryptResult,"utf-8");
decryptResult = decrypt(encryptResultStr.getBytes("utf-8"),password);
System.out.println("解密后：" + new String(decryptResult));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (Exception e) {
// TODO: handle exception
}
/*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*..)
at cn.com.songjy.test.ASCHelper.decrypt(ASCHelper.java:131)
at cn.com.songjy.test.ASCHelper.main(ASCHelper.java:58)
* */
/*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,
* 主要有两个方法:将二进制转换成16进制(见方法parseByte2HexStr)或是将16进制转换为二进制(见方法parseHexStr2Byte)*/ /*然后，我们再修订以上测试代码*/
System.out.println("***********************************************");
String encryptResultStr = parseByte2HexStr(encryptResult);
System.out.println("加密后：" + encryptResultStr);
byte[] decryptFrom = parseHexStr2Byte(encryptResultStr);
decryptResult = decrypt(decryptFrom,password);//解码
System.out.println("解密后：" + new String(decryptResult));
} /**
* 加密
* @method encrypt
* @param content 需要加密的内容
* @param password 加密密码
* @return
* @throws
* @since v1.0
*/
public static byte[] encrypt(String 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
byte[] byteContent = content.getBytes("utf-8");
cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
byte[] result = cipher.doFinal(byteContent);
return result; // 加密
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}catch (NoSuchPaddingException e) {
e.printStackTrace();
}catch (UnsupportedEncodingException e) {
e.printStackTrace();
}catch (InvalidKeyException e) {
e.printStackTrace();
}catch (IllegalBlockSizeException e) {
e.printStackTrace();
}catch (BadPaddingException e) {
e.printStackTrace();
}
return null;
} /**
* 解密
* @method decrypt
* @param content 待解密内容
* @param password 解密密钥
* @return
* @throws
* @since v1.0
*/
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; // 解密
} 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;
} /**
* 将二进制转换成16进制
* @method parseByte2HexStr
* @param buf
* @return
* @throws
* @since v1.0
*/
public static String parseByte2HexStr(byte buf[]){
StringBuffer sb = new StringBuffer();
for(int i = 0; i < buf.length; i++){
String hex = Integer.toHexString(buf[i] & 0xFF);
if (hex.length() == 1) {
hex = '0' + hex;
}
sb.append(hex.toUpperCase());
}
return sb.toString();
} /**
* 将16进制转换为二进制
* @method parseHexStr2Byte
* @param hexStr
* @return
* @throws
* @since v1.0
*/
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;
} /**
* 另外一种加密方式--这种加密方式有两种限制
* 1、密钥必须是16位的
* 2、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。
* @method encrypt2
* @param content 需要加密的内容
* @param password 加密密码
* @return
* @throws
* @since v1.0
*/
public static byte[] encrypt2(String content, String password){
try {
SecretKeySpec key = new SecretKeySpec(password.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");
byte[] byteContent = content.getBytes("utf-8");
cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
byte[] result = cipher.doFinal(byteContent);
return result; // 加密
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
return null;
}}
测试效果：
解密后：宋建勇
***********************************************
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*..)
at cn.com.songjy.test.ASCHelper.decrypt(ASCHelper.java:141)
at cn.com.songjy.test.ASCHelper.main(ASCHelper.java:58)
java.lang.NullPointerException
at java.lang.String.<init>(String.java:594)
at cn.com.songjy.test.ASCHelper.main(ASCHelper.java:59)
***********************************************
加密后：961000B09BDDA1F81E81EF3EFDC3A926
解密后：宋建勇
