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Java加密-对称加密算法详解

admin 2018年06月12日 编程语言 441 0

本位内容来自JAVA实现对称加密

Java加密-对称加密算法

对称加密算法是加密密钥等于解密密钥。常见的对称加密算法有:

  • DES,3DES
  • AES
  • PBE
  • IDEA

DES

DES(Data Encryption Standard)数据加密标准

这里写图片描述

jdk方式实现DES的加解密

public static void jdkDES() { 
 
    //生成密钥 
    try { 
        KeyGenerator keyGenerator = KeyGenerator.getInstance("DES"); 
        //指定keysize 
        keyGenerator.init(56); 
        SecretKey secretKey = keyGenerator.generateKey(); 
        byte[] bytesKey = secretKey.getEncoded(); 
 
        //key转换 
        DESKeySpec desKeySpec = new DESKeySpec(bytesKey); 
        SecretKeyFactory factory = SecretKeyFactory.getInstance("DES"); 
        Key convertSecretKey = factory.generateSecret(desKeySpec); 
 
        //加密  
        Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding"); 
        cipher.init(Cipher.ENCRYPT_MODE, convertSecretKey); 
        byte[] resultBytes =  cipher.doFinal(src.getBytes()); 
        System.out.println("jdk des encrypt : " + Hex.encodeHexString(resultBytes)); 
 
        //解密 
        cipher.init(Cipher.DECRYPT_MODE, convertSecretKey); 
        resultBytes = cipher.doFinal(resultBytes); 
        System.out.println("jdk des decrypt : " + new String(resultBytes)); 
 
    } catch (Exception e) { 
        e.printStackTrace(); 
    } 
 
 
    //jdk des encrypt : 719e81b53b891b1309b138c3e8c8a068cc6d476aaf51c288 
    //jdk des decrypt : imooc security des 
 
} 

DES应用
DES应用

3DES

jdk实现3DES

private static void jdk3des() { 
    // 生成密钥 
    try { 
        KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede"); 
        // 指定keysize 
        //keyGenerator.init(168); 
        //生成默认长度的KEY 
        keyGenerator.init(new SecureRandom()); 
        SecretKey secretKey = keyGenerator.generateKey(); 
        byte[] bytesKey = secretKey.getEncoded(); 
 
        // key转换 
        DESedeKeySpec desKeySpec = new DESedeKeySpec(bytesKey); 
        SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede"); 
        Key convertSecretKey = factory.generateSecret(desKeySpec); 
 
        // 加密 
        Cipher cipher = Cipher.getInstance("DESede/ECB/PKCS5Padding"); 
        cipher.init(Cipher.ENCRYPT_MODE, convertSecretKey); 
        byte[] resultBytes = cipher.doFinal(src.getBytes()); 
        System.out.println("jdk 3des encrypt : " + Hex.encodeHexString(resultBytes)); 
 
        // 解密 
        cipher.init(Cipher.DECRYPT_MODE, convertSecretKey); 
        resultBytes = cipher.doFinal(resultBytes); 
        System.out.println("jdk 3des decrypt : " + new String(resultBytes)); 
 
    } catch (Exception e) { 
        e.printStackTrace(); 
    } 
} 

AES

AES是目前使用最多的对称加密算法
AES的优势之一是至今尚未被破解,AES通常用于移动通信系统加密以及基于SSH协议的软件。

AES

jdk实现方式:

public static void jdkAES() { 
 
    try { 
        // 生成key 
        KeyGenerator keyGenerator = KeyGenerator.getInstance("AES"); 
        keyGenerator.init(128); 
        SecretKey secretKey = keyGenerator.generateKey(); 
        byte[] keybytes = secretKey.getEncoded(); 
 
        // key的转换 
        Key key = new SecretKeySpec(keybytes, "AES"); 
 
        // 加密 
        // AES/工作模式/填充方式 
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding"); 
        cipher.init(Cipher.ENCRYPT_MODE, key); 
        byte[] result = cipher.doFinal(src.getBytes()); 
        System.out.println("jdk aes encrypt : " + Base64.encodeBase64String(result)); 
 
        // 解密 
        cipher.init(Cipher.DECRYPT_MODE, key); 
        result = cipher.doFinal(result); 
        System.out.println("jdk aes decrypt : " + new String(result)); 
 
    } catch (Exception e) { 
        e.printStackTrace(); 
    } 
 
} 

AES实际应用流程:

AES实际应用流程

PBE

通过前面的例子,会发现AES、DES和3重DES在使用上比较一致。
PBE算法结合了消息摘要算法和对称加密算法的优点
PBE(Password Based Encryption)基于口令加密

jdk实现PBE:

public static void jdkPBE() { 
    try { 
        //初始化盐 
        SecureRandom random = new SecureRandom(); 
        byte[] salt = random.generateSeed(8); 
 
        //加密 
        //定义密码 
        String password = "imooc"; 
        //把密码转换成密钥 
        PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray()); 
        SecretKeyFactory factory = SecretKeyFactory.getInstance("PBEWITHMD5andDES"); 
        Key key = factory.generateSecret(pbeKeySpec); 
 
        //加密过程 
        PBEParameterSpec parameterSpec = new PBEParameterSpec(salt, 100); 
        Cipher cipher = Cipher.getInstance("PBEWITHMD5andDES"); 
        cipher.init(Cipher.ENCRYPT_MODE, key, parameterSpec); 
        byte[] result = cipher.doFinal(src.getBytes()); 
        System.out.println("jdk pbe encrypt : " + Base64.encodeBase64String(result)); 
 
        //解密 
        cipher.init(Cipher.DECRYPT_MODE, key, parameterSpec); 
        result = cipher.doFinal(result); 
        System.out.println("jdk pbe decrypt : " + new String(result)); 
 
    } catch (Exception e) { 
        e.printStackTrace(); 
    } 
 
 
} 

PBE实际应用流程:

实际应用流程

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