DES加密算法

package com.web;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

public class EncryptUtil {

public static byte[] encrypt(byte[] src, byte[] key) throws Exception {
// DES算法要求有一个可信任的随机数源
SecureRandom sr = new SecureRandom();
// 从原始密匙数据创建DESKeySpec对象
DESKeySpec dks = new DESKeySpec(key);
// 创建一个密匙工厂，然后用它把DESKeySpec转换成一个SecretKey对象
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
SecretKey securekey = keyFactory.generateSecret(dks);
// Cipher对象实际完成加密操作
Cipher cipher = Cipher.getInstance(DES);
// 用密匙初始化Cipher对象
cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
// 正式执行加密操作
return cipher.doFinal(src);
}

/**
* @param password 密码
* @param key 加密字符串
* @return
* @throws Exception
*/
public final static String encrypt(String password, String key) throws Exception {
try {
return byte2String(encrypt(password.getBytes(), key.getBytes("gbk")));
} catch (Exception e) {
throw new Exception("加密失败");
}
}

public static String byte2String(byte[] b) {
String hs = "";
String stmp = "";
for (int n = 0; n < b.length; n++) {
stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
if (stmp.length() == 1)
hs = hs + "0" + stmp;
else
hs = hs + stmp;
}
return hs.toUpperCase();
}

private final static String DES = "DES";

/**
* @param src 数据源
* @param key 密钥，长度必须是8的倍数
* @return
* @throws Exception
*/
public static byte[] decrypt(byte[] src, byte[] key) throws Exception {
// DES算法要求有一个可信任的随机数源
SecureRandom sr = new SecureRandom();
// 从原始密匙数据创建一个DESKeySpec对象
DESKeySpec dks = new DESKeySpec(key);
// 创建一个密匙工厂，然后用它把DESKeySpec对象转换成一个SecretKey对象
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
SecretKey securekey = keyFactory.generateSecret(dks);
// Cipher对象实际完成解密操作
Cipher cipher = Cipher.getInstance(DES);
// 用密匙初始化Cipher对象
cipher.init(Cipher.DECRYPT_MODE, securekey, sr);

// 正式执行解密操作
return cipher.doFinal(src);
}

public final static String decrypt(String data, String key) throws Exception {
try {
return new String(decrypt(String2byte(data.getBytes()), key.getBytes()),"gbk");
} catch (Exception e) {
throw new Exception("解密失败");
}
}

public static byte[] String2byte(byte[] b) {
if ((b.length % 2) != 0)
throw new IllegalArgumentException("长度不是偶数");
byte[] b2 = new byte[b.length / 2];
for (int n = 0; n < b.length; n += 2) {
String item = new String(b, n, 2);
b2[n / 2] = (byte) Integer.parseInt(item, 16);
}
return b2;
}

public static void main(String[] args) {
String encryptString = null;
try {
encryptString = encrypt("{"username":"1000281","password":"8742","itype":"2"}","@Ew6DS6&*xN!43DR");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(encryptString);

String desencryptString = null;
try {
desencryptString = decrypt("D68800A172D2FA2A2048CBF6E1729449F99942F43CC4BE3EE096D40C3F981479098AFF278D98D0CB0720E1E2E277A2935D91BAC3BAC08655", "@Ew6DS6&*xN!43DR");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(desencryptString);
}

}