AES加密算法实现

AES算法是一种对称加密算法，是美国国家标准技术研究所NIST旨在取代DES的21世纪的加密标准。

下文实例中，密钥采用了直接写死的方式，实际使用中可以配合RSA加密算法加密密钥，从而达到更好的安全效果。

=====================代码实现====================

package com.zhuiyv.util;

import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.apache.axis.encoding.Base64;

/**
* AES加解密工具类
* @.Desc AES对称加密算法，调用方法： 
* 1) 对明文进行加密，并对密文进行Base64编码：AESUtil.encrypt(plainText, keyStr); plainText为需要加密的字符串，keyStr为密钥。 
* 2) 先对密文进行Base64解码，然后再进行解密：AESUtil.decrypt(secretText, keyStr); secretText为需要解密的字符串，keyStr为密钥。
* @author Zhuiyv
* @version 1.0.0
* @.Date 2015-11-11 10:04:20
* @.Modify
*/
public class AESUtil {
/**
* AES Key 长度
*/
private static final int AES_KEY_LENGTH = 16;

/**
* 默认AES Key
*/
private static final String DEFAULT_AES_KEY_STR = "AES_KEY";

// 此处向量可自定义，请注意如果超过0x80请加(byte)强制转换
private static final byte[] OIV = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10 };

/**
* 加密，并对密文进行Base64编码，采用默认密钥
* @param plainText
* 明文
* @return String
* 做了Base64编码的密文
* @throws Exception
*/
public static String encrypt(String plainText){
return encrypt(plainText, DEFAULT_AES_KEY_STR);
}

/**
* 加密，并对密文进行Base64编码，可指定密钥
* @param plainText
* 明文
* @param keyStr
* 密钥
* @return String
* 做了Base64编码的密文
* @throws Exception
*/
public static String encrypt(String plainText, String keyStr){
try {
byte[] keyBytes = keyStr.getBytes("UTF-8");
byte[] keyBytesTruncated = new byte[AES_KEY_LENGTH];
for (int i = 0; i < AES_KEY_LENGTH; i++) {
if (i >= keyBytes.length) {
// keyBytesTruncated[i] = (byte)0x80;
keyBytesTruncated[i] = 0x12;
} else {
keyBytesTruncated[i] = keyBytes[i];
}
}
Key ckey = new SecretKeySpec(keyBytesTruncated, "AES");
Cipher cp = Cipher.getInstance("AES/CBC/PKCS5Padding");
IvParameterSpec iv = new IvParameterSpec(OIV);
cp.init(1, ckey, iv);
byte[] inputByteArray = plainText.getBytes("UTF-8");

byte[] cipherBytes = cp.doFinal(inputByteArray);
// String result=Base64.encodeToString(cipherBytes, Base64.NO_WRAP);
String result = encodeBase64(cipherBytes);
result = result.replace("+", "%2b");
result = result.replace("
", "").replace("
", "");
return result;
} catch (Exception e) {
throw new RuntimeException(e);
}
}

/**
* 对做了Base64编码的密文进行解密，采用默认密钥
* @param secretText
* 做了Base64编码的密文
* @return String
* 解密后的字符串 
* @throws Exception
*/
public static String decrypt(String secretText){
return decrypt(secretText, DEFAULT_AES_KEY_STR);
}

/**
* 对做了Base64编码的密文进行解密
* @param secretText
* 做了Base64编码的密文
* @param keyStr
* 密钥
* @return String
* 解密后的字符串 
* @throws Exception
*/
public static String decrypt(String secretText, String keyStr){
secretText = secretText.replace("%2b", "+");
try {
byte[] cipherByte = Base64.decode(secretText);
// byte[] cipherByte =Base64.decode(plainText, Base64.DEFAULT);
byte[] keyBytes = keyStr.getBytes("UTF-8");
byte[] keyBytesTruncated = new byte[AES_KEY_LENGTH];
for (int i = 0; i < AES_KEY_LENGTH; i++) {
if (i >= keyBytes.length) {
keyBytesTruncated[i] = 0x12;
} else {
keyBytesTruncated[i] = keyBytes[i];
}
}
Key ckey = new SecretKeySpec(keyBytesTruncated, "AES");
Cipher cp = Cipher.getInstance("AES/CBC/PKCS5Padding");
// Cipher cp = Cipher.getInstance("AES/ECB/PKCS5Padding");
IvParameterSpec iv = new IvParameterSpec(OIV);
cp.init(2, ckey, iv);
byte[] decryptBytes = cp.doFinal(cipherByte);
return new String(decryptBytes, "UTF-8").replace("", "");
} catch (Exception e) {
throw new RuntimeException(e);
}    
}

// 测试
public static void main(String[] args) {
try {
String content = "{'imei':'NDEyMzQzMjI0MjMzMg==','mac':'MTI6MzQ6MTI6MjM6NDI6MTI=','version':'MS4w'}";
System.out.println(content.length());    
System.out.println("加密前：" + content);
// 加密
String encryptResult = encrypt(content);
System.out.println("加密后：" + encryptResult);
String base64_encryptResult = encodeBase64(encryptResult);
System.out.println("Base64编码后：" + base64_encryptResult);
// 解密
String decryptResult = decrypt(encryptResult);//decrypt("MfNVg%2bLiK9QzCien5EirmDRenFRwmuteJH0xlPi04k4aHqVne8sjmxtkwM9uL7I6OGC4gzSxbs13h9kpsWLqxA==");//decrypt(base64_encryptResult);
System.out.println("解密后：" + decryptResult);
} catch (Exception ex) {
ex.printStackTrace();
}
}

private static String encodeBase64(String s){
return Base64.encode(s.getBytes());
}

private static String encodeBase64(byte[] b){
return Base64.encode(b);
}
}