• java加密算法


    不可逆加密

    MD5加密

    package com.system.util;
    
    import java.security.MessageDigest;
    
    public class MD5Util {
        public final static String MD5(String s) {
            char hexDigits[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};       
            try {
                byte[] btInput = s.getBytes();
                // 获得MD5摘要算法 MessageDigest 对象
                MessageDigest mdInst = MessageDigest.getInstance("MD5");
                // 使用指定的字节更新摘要
                mdInst.update(btInput);
                // 获得密文
                byte[] md = mdInst.digest();
                // 把密文转换成十六进制的字符串形式
                int j = md.length;
                char str[] = new char[j * 2];
                int k = 0;
                for (int i = 0; i < j; i++) {
                    byte byte0 = md[i];
                    str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                    str[k++] = hexDigits[byte0 & 0xf];
                }
                return new String(str);
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }
        }
    }

    对称加密

    DES加密

    package com.gmtx.system.tools;
    
    import java.security.SecureRandom;
    import java.util.Random;
    import javax.crypto.*;
    import javax.crypto.spec.DESKeySpec;
    import org.apache.commons.codec.binary.Base64;
    
    /**
     DES加密介绍
     DES是一种对称加密算法,所谓对称加密算法即:加密和解密使用相同密钥的算法。DES加密算法出自IBM的研究,
     后来被美国政府正式采用,之后开始广泛流传,但是近些年使用越来越少,因为DES使用56位密钥,以现代计算能力,
     24小时内即可被破解。虽然如此,在某些简单应用中,我们还是可以使用DES加密算法
     注意:DES加密和解密过程中,密钥长度都必须是8的倍数
     */
    public class DES {
    
        public static void main(String[] args) throws Exception {
            //动态创建16位秘钥,可以写死
            String password = createSecKey(16);
            System.out.println(password);
    
            String str = "测试内容";
            /*测试加密*/
            String rs = encrypt(str, password);
            System.out.println("加密后: "+rs);
    
            /*测试解密*/
            String rs_des = decrypt(rs,password);
            System.out.println("解密后: "+rs_des);
    
        }
    
        private static String[] ss = { "a", "b", "c", "d", "e", "f", "g", "h", "i",
                "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
                "w", "x", "y", "z", "A", "B", "C", "D", "E", "F", "G", "H", "I",
                "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V",
                "W", "X", "Y", "Z", "1", "2", "3", "4", "5", "6", "7", "8", "9",
                "0" };
    
        /**
         * 根据长度生成密钥
         * @param length 长度须是8
         * @return
         * @throws Exception
         */
        public static String createSecKey(int length) {
            if (length % 8 != 0) {
                return null;
            }
            String result = "";
            for (int i = 0; i < length; i++) {
                Random r = new Random();
                int n = r.nextInt(ss.length);
                result += ss[n];
            }
            return result;
        }
    
        /**
         * 加密
         * @param data 待加密数据
         * @param key  秘钥
         * @return
         * @throws Exception
         */
        public static String encrypt(String data, String key){
            try {
                byte[] bt = encrypt(data.getBytes("utf-8"), key);
                String strs = Base64.encodeBase64String(bt);
                return strs;
            } catch (Exception ex) {
                ex.printStackTrace();
            }
            return "";
        }
    
        /**
         * 解密
         * @param data 待解密字符串
         * @param key 秘钥
         * @return
         * @throws Exception
         */
        public static String decrypt(String data, String key) throws Exception {
            byte[] buf = Base64.decodeBase64(data);
            byte[] bt = decrypt(buf, key);
            return new String(bt, "UTF-8");
        }
    
        /**
         * 加密 - byte数组
         * @param datasource
         * @param password
         * @return
         */
        private static byte[] encrypt(byte[] datasource, String password) {
            try {
                SecureRandom random = new SecureRandom();
                DESKeySpec desKey = new DESKeySpec(password.getBytes());
                //创建一个密匙工厂,然后用它把DESKeySpec转换成SecretKey
                SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
                SecretKey securekey = keyFactory.generateSecret(desKey);
                //Cipher对象实际完成加密操作
                Cipher cipher = Cipher.getInstance("DES");
                //用密匙初始化Cipher对象
                cipher.init(Cipher.ENCRYPT_MODE, securekey, random);
                //现在,获取数据并加密
                //正式执行加密操作
                return cipher.doFinal(datasource);
            } catch (Throwable e) {
                e.printStackTrace();
            }
            return null;
        }
    
        /**
         * 解密 - byte数组
         * @param src 加密字符串的二进制数组
         * @param password 解密密码
         * @return 原字符串的二进制数组
         * @throws Exception
         */
        private static byte[] decrypt(byte[] src, String password) throws Exception {
            //DES算法要求有一个可信任的随机数源
            SecureRandom random = new SecureRandom();
            //创建一个DESKeySpec对象
            DESKeySpec desKey = new DESKeySpec(password.getBytes());
            //创建一个密匙工厂
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            //将DESKeySpec对象转换成SecretKey对象
            SecretKey securekey = keyFactory.generateSecret(desKey);
            //Cipher对象实际完成解密操作
            Cipher cipher = Cipher.getInstance("DES");
            //用密匙初始化Cipher对象
            cipher.init(Cipher.DECRYPT_MODE, securekey, random);
            // 真正开始解密操作
            return cipher.doFinal(src);
        }
    }

    测试内容

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  • 原文地址:https://www.cnblogs.com/aeolian/p/12091891.html
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