DES加密--不安全加密

package test;

import java.security.InvalidKeyException;

import java.security.Key;

import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.SecretKeyFactory;

//import javax.crypto.SecretKeyFactory;

import javax.crypto.spec.DESKeySpec;

public class DESCoder
{

        //加密算法

        public static final String KEY_ALGORITHM= "DES";

       

        //加密/解密算法 /工作模式/填充模式

        public static final String CIPHER_ALGORITHM= "DES/ECB/PKCS5Padding";

       

        //还原密钥

        private static Key
toKey(byte[] key) throws InvalidKeyException,
NoSuchAlgorithmException, Exception{

               //实例化DES密钥材料

              DESKeySpec dks= new DESKeySpec(key);

               //实例化密钥工厂

              SecretKeyFactory keyFactory=SecretKeyFactory.getInstance( KEY_ALGORITHM);

               //生成密钥

              SecretKey secretKey= keyFactory.generateSecret(dks);

               return 
secretKey;

       }

       

        //解密

        public static byte[]
decrpt(byte[] data, byte[]
key) throws InvalidKeyException, NoSuchAlgorithmException,
Exception{

               //还原密钥

              Key k= toKey(key);

               //实例化

              Cipher cipher=Cipher. getInstance(CIPHER_ALGORITHM);

               //初始化

              cipher.init(Cipher. DECRYPT_MODE,k);

               return cipher.doFinal(data);

       }

       

        //加密

        public static byte[]
encrypt(byte[] data, byte[]
key) throws Exception{

               //还原密钥

              Key k= toKey(key);

              Cipher cipher=Cipher. getInstance(CIPHER_ALGORITHM);

              cipher.init(Cipher. ENCRYPT_MODE,
k);

               return cipher.doFinal(data);

       }

       

        //获取密钥，二进制形式

        public static byte[]
initKey() throws Exception{

              KeyGenerator kg=KeyGenerator. getInstance(KEY_ALGORITHM);

               //初始化密钥生成器

              kg.init(56); //kg.init(64),kg.init(new
SecureRandom());

               //生成密钥

              SecretKey secretKey=kg.generateKey();

               //获取密钥的二进制形式

               return secretKey.getEncoded();

       }

}

---

多重DES

加密算法 KEY_ALGORITHM ="DESede"

CIPHER_ALGORITHM ="DESede/ECB/PKCS5Padding

密钥规范 DEedeSKeySpec
dks=new DESedeKeySpec(key)

密钥长度也要修改 kg.init(168);