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

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

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。

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：

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：