TestDESede

//好神奇，密钥每次都不一样，但是就是能成功解密。
//Cipher 是为加密和解密提供密码功能。差不多就是。。。。给密钥一个附加密码。加解密操作的时候不仅需要拿到密钥，还需要这个密码
//所以上面说的密钥不一样，其实是每次的密码都不一样
import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;

import org.apache.commons.codec.binary.Base64;

public class TestDESede {

public static String KEY_ALGORITHM ="DESede";

public static String CIPHER_ALOGITHM ="DESede/ECB/PKCS5Padding";

public static void main(String[] args) throws Exception{
String s = "DESede";
System.out.println("原文： " + s);
byte[] key = initKey();
System.out.println("密钥： " + Base64.encodeBase64String(key));
byte[] afterEncrypt = encrypt(s.getBytes(), key);
System.out.println("加密后:" + Base64.encodeBase64String(afterEncrypt));

byte[] afterDecrypt = decrypt(afterEncrypt, key);
System.out.println("解密后：" + new String(afterDecrypt));

}

public static byte[] initKey() throws Exception {
KeyGenerator kg = KeyGenerator.getInstance(KEY_ALGORITHM);
kg.init(168);
SecretKey sk = kg.generateKey();
return sk.getEncoded();
}

/**
* 转换密钥
* @param key
* @return
* @throws Exception
*/
public static Key toKey(byte[] key) throws Exception {
//获取密钥模具，规范
DESedeKeySpec dks = new DESedeKeySpec(key);
//获取密钥工厂
SecretKeyFactory skf = SecretKeyFactory.getInstance(KEY_ALGORITHM);
//生成密钥
return skf.generateSecret(dks);
}

public static byte[] encrypt(byte[] date, byte[] key) throws Exception {
//还原密钥
Key k = toKey(key);
Cipher cipher = Cipher.getInstance(CIPHER_ALOGITHM);
cipher.init(Cipher.ENCRYPT_MODE, k);
return cipher.doFinal(date);
}

/**
* 解密
* @param date
* @param key
* @return
* @throws Exception
*/
public static byte[] decrypt(byte[] date, byte[] key) throws Exception {
//还原密钥
Key k = toKey(key);
Cipher cipher = Cipher.getInstance(CIPHER_ALOGITHM);
cipher.init(Cipher.DECRYPT_MODE, k);
return cipher.doFinal(date);
}

}