对称加密算法

来源：互联网发布：房屋建筑设计软件编辑：程序博客网时间：2024/05/10 23:24

对称加密算法，顾名思义其加密与解密过程相同，应用于软、硬件。

1.DES

安全性低，密钥长度：JDK–>56，BC–>64
代码实现：

            //生成key            KeyGenerator kg = KeyGenerator.getInstance("DES");            kg.init(56);            SecretKey sk = kg.generateKey();            byte[] bytesKey = sk.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[] result = cipher.doFinal(src.getBytes());            System.out.println("jdk des encrypt:"+Hex.encodeHexString(result));            //解密            cipher.init(Cipher.DECRYPT_MODE, convertSecretKey);            result = cipher.doFinal(result);            System.out.println("jdk des descrypt:"+new String(result));

2.3重DES
密钥长度增强，迭代次数提高。
代码实现：

            //生成key            KeyGenerator kg = KeyGenerator.getInstance("DESede");            kg.init(168);            //或者 kg.init(new SecureRandom());  获取默认key长度            SecretKey sk = kg.generateKey();            byte[] bytesKey = sk.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[] result = cipher.doFinal(src.getBytes());            System.out.println("jdk 3des encrypt:"+Hex.encodeHexString(result));            //解密            cipher.init(Cipher.DECRYPT_MODE, convertSecretKey);            result = cipher.doFinal(result);            System.out.println("jdk 3des descrypt:"+new String(result));

3.AES
AES是使用最多的，弥补了DES有漏洞、3DES效率低的缺点，而且至今未被破译，通常用于移动通讯系统加密以及基于SSH协议的软件。
代码实现：

            //生成key            KeyGenerator kg = KeyGenerator.getInstance("AES");            kg.init(128);            SecretKey sk = kg.generateKey();            byte[] bytesKey = sk.getEncoded();            //key转换            Key key = new SecretKeySpec(bytesKey,"AES");            //加密            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:"+Hex.encodeHexString(result));            //解密            cipher.init(Cipher.DECRYPT_MODE, key);            result = cipher.doFinal(result);            System.out.println("jdk aes descrypt:"+new String(result));

4.PBE
PBE是基于口令加密，结合了消息摘要算法与对称加密算法的优点，其特点是密文以“==”结尾。
加密过程进行加盐处理，它的作用是扰码，防破译。
代码实现：

            //初始化盐            SecureRandom random = new SecureRandom();            byte[] salt = random.generateSeed(8);            //口令与密钥            String password = "imooc";            PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray());            SecretKeyFactory factory = SecretKeyFactory.getInstance("PBEWITHMD5andDES");            Key key = factory.generateSecret(pbeKeySpec);            //加密            PBEParameterSpec pps = new PBEParameterSpec(salt,100);            Cipher cipher = Cipher.getInstance("PBEWITHMD5andDES");            cipher.init(Cipher.ENCRYPT_MODE,key,pps);            byte[] result = cipher.doFinal(src.getBytes());            System.out.println("jdk pbe encrypt:"+Base64.encodeBase64String(result));            //解密            cipher.init(Cipher.DECRYPT_MODE,key,pps);            result = cipher.doFinal(result);            System.out.println("jdk pbe decrypt:"+new String(result));

0 0