Java加密解密相关

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关于解释加密解密中的填充方案：

http://laokaddk.blog.51cto.com/368606/461279/

关于对称加密中的反馈模式：

http://blog.csdn.net/aaaaatiger/article/details/2525561

:写法为：

DES/CBC/PKCS5Padding

各种加密算法的加密解密写法：已有DES,MD5,SHA（未结束）

package com.qin.test;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.math.BigInteger;import java.security.InvalidKeyException;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;import java.security.SecureRandom;import java.security.spec.InvalidKeySpecException;import javax.crypto.BadPaddingException;import javax.crypto.Cipher;import javax.crypto.IllegalBlockSizeException;import javax.crypto.NoSuchPaddingException;import javax.crypto.SecretKey;import javax.crypto.SecretKeyFactory;import javax.crypto.spec.DESKeySpec;public class Main {public static void main(String[] args) throws InvalidKeyException,NoSuchAlgorithmException, InvalidKeySpecException,IllegalBlockSizeException, BadPaddingException,NoSuchPaddingException, IOException {Main m = new Main();// m.desJie(m.desJia());// m.createMD5Code();m.createSHACode();}/********************************************************************************* * 对称DES加密解密 DES（Data Encryption Standard）是发明最早的最广泛使用的分组对称加密算法。 * DES算法的入口参数有三个 * ：Key、Data、Mode。其中Key为8个字节共64位，是DES算法的工作密钥；Data也为8个字节64位，是要被加密或被解密的数据； * Mode为DES的工作方式，有两种：加密或解密。 */private String desKey = "12345678";// des加密key必须为8位长度public byte[] desJia() throws InvalidKeyException,NoSuchAlgorithmException, InvalidKeySpecException,NoSuchPaddingException, IllegalBlockSizeException,BadPaddingException {// 因为普通的Random是线性可预测的，安全性不高，而这个安全性比较高SecureRandom s = new SecureRandom();// 创建Deskey对象DESKeySpec DESKey = new DESKeySpec(desKey.getBytes());// 创建DES密钥工厂SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");// 使用密钥工厂来生成符合规范的密钥对象SecretKey secretKey = keyFactory.generateSecret(DESKey);// 进行实际的加密Cipher c = Cipher.getInstance("DES/ECB/PKCS5Padding");// 初始化c.init(Cipher.ENCRYPT_MODE, secretKey, s);// 开始加密byte[] b = c.doFinal("我是加密的内容".getBytes());for (byte bb : b) {System.out.println("" + bb);}return b;}public void desJie(byte[] neirong) throws InvalidKeyException,NoSuchAlgorithmException, InvalidKeySpecException,IllegalBlockSizeException, BadPaddingException,NoSuchPaddingException {// 因为普通的Random是线性可预测的，安全性不高，而这个安全性比较高SecureRandom s = new SecureRandom();// 创建Deskey对象DESKeySpec DESKey = new DESKeySpec(desKey.getBytes());// 创建DES密钥工厂SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");// 使用密钥工厂来生成符合规范的密钥对象SecretKey secretKey = keyFactory.generateSecret(DESKey);// 进行实际的解密Cipher c = Cipher.getInstance("DES/ECB/PKCS5Padding");// 初始化c.init(Cipher.DECRYPT_MODE, secretKey, s);// 开始解密byte[] hehe = c.doFinal(neirong);System.out.println(new String(hehe));}/********************************************************************************************* * MD5消息摘要算法 MD5的典型应用是对一段Message(字节串)产生fingerprint(指纹），以防止被“篡改”。 * 相同的内容会产生相同的md5值 *  */public void createMD5Code() throws NoSuchAlgorithmException, IOException {MessageDigest md5 = MessageDigest.getInstance("MD5");File f = new File("D:\\bb.txt");// 验教文件的md5值FileInputStream fileInputStream = new FileInputStream(f);byte[] bytes = new byte[256];int len = -1;while ((len = fileInputStream.read(bytes)) > -1) {md5.update(bytes, 0, len);}fileInputStream.close();byte[] md5Code = md5.digest();System.out.println("我的" + f.getName() + " md5 :"+ new BigInteger(1, md5Code).toString(16));}/** * SHA类似MD5，不过产生的长度比md5长 */public void createSHACode() throws NoSuchAlgorithmException, IOException {MessageDigest md5 = MessageDigest.getInstance("SHA");File f = new File("D:\\bb.txt");// 验教文件的SHA值FileInputStream fileInputStream = new FileInputStream(f);byte[] bytes = new byte[256];int len = -1;while ((len = fileInputStream.read(bytes)) > -1) {md5.update(bytes, 0, len);}fileInputStream.close();byte[] md5Code = md5.digest();System.out.println("我的" + f.getName() + " SHA :"+ new BigInteger(1, md5Code).toString(16));}}

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