java AES 加密与解密

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。

闲话少说，代码如下：

package com.ss.util.secret;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
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;

/**
**
* AES128 算法，加密模式为ECB，填充模式为 pkcs7（实际就是pkcs5）
*
*
*/
public class AESUtils {

/**
* 加密
*
* @param content 需要加密的内容
* @param key  加密密码
* @return
*/
public static byte[] encrypt(String content, String key) {
try {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128, new java.security.SecureRandom(key.getBytes()));
SecretKey secretKey = kgen.generateKey();
byte[] enCodeFormat = secretKey.getEncoded();
SecretKeySpec secretKeySpec = 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, secretKeySpec);// 初始化
byte[] result = cipher.doFinal(byteContent);
return result; // 加密
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
return null;
}

/**解密
* @param content  待解密内容
* @param key 解密密钥
* @return
*/
public static byte[] decrypt(byte[] content, String key) {
try {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128, new java.security.SecureRandom(key.getBytes()));
SecretKey secretKey = kgen.generateKey();
byte[] enCodeFormat = secretKey.getEncoded();
SecretKeySpec secretKeySpec = new SecretKeySpec(enCodeFormat, "AES");
Cipher cipher = Cipher.getInstance("AES");// 创建密码器
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);// 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;
}

/**
* 字符串加密
* @param content 要加密的字符串
* @param key 加密的AES Key
* @return
*/
public static String encryptString(String content, String key) {
return parseByte2HexStr( encrypt(content, key));
}

/**
* 字符串解密
* @param content 要解密的字符串
* @param key 解密的AES Key
* @return
*/
public static String decryptString(String content, String key){
byte[] decryptFrom = parseHexStr2Byte(content);
byte[] decryptResult = decrypt(decryptFrom,key);
return new String(decryptResult);
}

/**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;
}

/**将二进制转换成16进制
* @param buf
* @return
*/
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();
}

public static void  main(String aregs[]){
String content = "协议加密Test&123";
String key = "25d55ad283aa400af464c76d713c07ad";
try {
//加密
System.out.println("加密前：" + content);
String encrypt = AESUtils.encryptString(content, key);
System.out.println("加密后：" + encrypt);
//解密
String decrypt = AESUtils.decryptString(encrypt, key);
System.out.println("解密后：" + decrypt);
} catch (Exception e) {
e.printStackTrace();
}

}
}

运行结果：

加密前：协议加密Test&123

加密后：7D07155438880C51E50433C17D9AFF8DCB2A9596AF46B2ABA33C18918053E3E0

解密后：协议加密Test&123