Java实现加密算法之对称加密

一：特点

    加密密钥和解密密钥是一样的，安全性没有那么高

二：对称加密算法

    -DES --3DES   

    -AES

    -PBE

    -IDEA

三：DES算法（Data Encryption Standard）：数据加密标准

    public  static void jdkDes(){
        try {
            //生成KEY
            KeyGenerator keyGenerator = KeyGenerator.getInstance("DES");
            //指定KeySize
            keyGenerator.init(56);
            SecretKey secretKey=keyGenerator.generateKey();
            byte[] keyBytes=secretKey.getEncoded();

            //KEY转换
            DESKeySpec desKeySpec=new DESKeySpec(keyBytes);
            SecretKeyFactory secretKeyFactory=SecretKeyFactory.getInstance("DES");
            Key key=secretKeyFactory.generateSecret(desKeySpec);

            //加密
            Cipher cipher=Cipher.getInstance("DES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE,key);
            byte[] Encoderesults=cipher.doFinal(src.getBytes());
            System.out.println("加密后的密文为："+ org.apache.commons.codec.binary.Hex.encodeHexString(Encoderesults));

            //解密
            Cipher cipher1=Cipher.getInstance("DES/ECB/PKCS5Padding");
            cipher1.init(Cipher.DECRYPT_MODE,key);
            byte[] decodResult=cipher1.doFinal(Encoderesults);
            System.out.println("解密后的密文为："+ new String(decodResult));
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    2）：3DES算法

    private static String src="使用3des实现对称加密";
    //使用jdk
    public static void jdk3Des(){

        try{
            //生成key
          KeyGenerator keyGenerator=  KeyGenerator.getInstance("DESede");
          //keyGenerator.init(168);
            keyGenerator.init(new SecureRandom());
          SecretKey secretKey=keyGenerator.generateKey();
          byte[] byteKey=secretKey.getEncoded();

          //key的转换
            DESedeKeySpec desKeySpec=new DESedeKeySpec(byteKey);
            SecretKeyFactory secretKeyFactory=SecretKeyFactory.getInstance("DESede");
            Key key=secretKeyFactory.generateSecret(desKeySpec);

            //加密
            Cipher ciper=Cipher.getInstance("DESede/ECB/PKCS5Padding");
            ciper.init(Cipher.ENCRYPT_MODE,key);
            byte[] encodeResult=ciper.doFinal(src.getBytes());
            System.out.println("加密后的密文为："+ Hex.encodeHexString(encodeResult));

            //解密
            ciper.init(Cipher.DECRYPT_MODE,key);
            byte[] decodeResult=ciper.doFinal(encodeResult);
            System.out.println("解密后的密文为："+new String(decodeResult));
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    3）：AES加密算法（通常用于移动通信系统加密以及基于ssh协议的软件）

/**
 * 使用AES加密算法
 */
public class AESUtil {
    private  static String src="使用AES来进行加密";

    //jdk
    public static void jdkAes(){
        try {
            //生成key
            KeyGenerator keyGenerator=KeyGenerator.getInstance("AES");
            keyGenerator.init(new SecureRandom());
            SecretKey secretKey=keyGenerator.generateKey();
            byte[] keyBytes=secretKey.getEncoded();

            //转换key
            Key key=new SecretKeySpec(keyBytes,"AES");

            //加密
            Cipher cipher=Cipher.getInstance("AES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE,key);
            byte[] encodeResult=cipher.doFinal(src.getBytes());
            System.out.println("加密后的密文为："+ Base64.encodeBase64String(encodeResult));

            //解密
            cipher.init(Cipher.DECRYPT_MODE,key);
            byte[] decodeResult=cipher.doFinal(encodeResult);
            System.out.println("解密后的密文为："+new String(decodeResult));

        }catch (Exception e){
            e.printStackTrace();
        }
    }

    //AES的BC实现
    public static void BcAES(){
        Security.addProvider(new BouncyCastleProvider());
        try {
            //生成key
            KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
            keyGenerator.getProvider();
            keyGenerator.init(new SecureRandom());
            SecretKey secretKey=keyGenerator.generateKey();
            byte[] keyByte=secretKey.getEncoded();

            //转换key
            Key key=new SecretKeySpec(keyByte,"AES");

            //加密
            Cipher cipher=Cipher.getInstance("AES");
            cipher.init(Cipher.ENCRYPT_MODE,key);
            byte[] encodeResult=cipher.doFinal(src.getBytes());
            System.out.println("加密后的密文为："+ Base64.encodeBase64String(encodeResult));

            //解密
            cipher.init(Cipher.DECRYPT_MODE,key);
            byte[] decodeResult=cipher.doFinal(encodeResult);
            System.out.println("解密后的密文为："+new String(decodeResult));
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    4）：PBE加密算法（Password Based Encryption）基于口令加密

public class PBEUtil {
    private static String src="使用PBE进行加密";
    //使用jdk
    public static void jdkPBE(){
        try {
            //初始化盐
            SecureRandom random = new SecureRandom();
            byte[] salt = random.generateSeed(8);

            //口令与密钥
            String password = "password";
            PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray());
            SecretKeyFactory factory = SecretKeyFactory.getInstance("PBEWITHMD5andDES");
            Key key=factory.generateSecret(pbeKeySpec);

            //加密
            PBEParameterSpec pbeParameterSpec=new PBEParameterSpec(salt,100);
            Cipher cipher=Cipher.getInstance("PBEWITHMD5andDES");
            cipher.init(Cipher.ENCRYPT_MODE,key,pbeParameterSpec);
            byte[] encodeResult=  cipher.doFinal(src.getBytes());
            System.out.println("加密后的密文为："+ Base64.encodeBase64String(encodeResult));

            //解密
            cipher.init(Cipher.DECRYPT_MODE,key,pbeParameterSpec);
            byte[] decodeREsult=cipher.doFinal(encodeResult);
            System.out.println("解密后的密文为："+new String(decodeREsult));
        }catch (Exception e){
            e.printStackTrace();
        }
    }

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