加密算法 - 小传风

1、Base64

采用Base64编码具有不可读性，多用于网络中传输的数据进行编码，严格意义上属于 编码的格式 ，有64个字符的对应的编码，Base64就是将内容按照该格式进行编码。可以对数据编码和解码，是可逆的，安全度较低，不过，也可以作为最基础最简单的加密算法用于加密要求较弱的情况。
JDk实现主要使用用BASE64Encoder和BASE64Decoder类的方法（注意：在Eclipse中使用JDK的Base64可能会出现找不到的问题，是因为Base64Encoder并不属于JDK标准库范畴，但是又包含在了JDK中，需要我们手动导入\jre\lib目录下的rt.jar包即可）。
1、标准的Base64并不适合直接放在URL里传输；
2、不是加密算法，而是一种将数据编码为64位二进制字符；
package com.paic.java8;
import java.io.UnsupportedEncodingException;
import java.util.Arrays;
import java.util.Base64;
import java.util.UUID;
public class Base64Demo {
    public static void main(String args[]) {
        try {
            // 使用基本编码
            String bStr = "I am a hero!";
            System.out.println("字符串:"+bStr);
            String base64encodedString = Base64.getEncoder().encodeToString(bStr.getBytes("utf-8"));
            System.out.println("基本（编码） :" + base64encodedString);
            // 解码
            byte[] base64decodedBytes = Base64.getDecoder().decode(base64encodedString);
            System.out.println("基本(解码): " + new String(base64decodedBytes, "utf-8"));
            //-----------------------
            String urlStr = "TutorialsPoint?java8";
            System.out.println("URL字符串:"+urlStr);
            base64encodedString = Base64.getUrlEncoder().encodeToString(urlStr.getBytes("utf-8"));
            System.out.println("URL(编码) :" + base64encodedString);
            base64decodedBytes = Base64.getUrlDecoder().decode(base64encodedString);
            System.out.println("URL(解码): " + new String(base64decodedBytes, "utf-8"));
            //---------------------------
            StringBuilder stringBuilder = new StringBuilder();
            for (int i = 0; i < 10; ++i) {
                stringBuilder.append(UUID.randomUUID().toString());
            System.out.println("MIME字符串 :"+stringBuilder.toString());
            byte[] mimeBytes = stringBuilder.toString().getBytes("utf-8");
            String mimeEncodedString = Base64.getMimeEncoder().encodeToString(mimeBytes);
            System.out.println("MIME(编码) :" + mimeEncodedString);
            base64decodedBytes = Base64.getMimeDecoder().decode(mimeEncodedString);
            System.out.println("MIME(解码): " + new String(base64decodedBytes, "utf-8"));
        } catch (UnsupportedEncodingException e) {
            System.out.println("Error :" + e.getMessage());
字符串:I am a hero!
基本（编码） :SSBhbSBhIGhlcm8h
基本(解码): I am a hero!
URL字符串:TutorialsPoint?java8
URL(编码) :VHV0b3JpYWxzUG9pbnQ_amF2YTg=
URL(解码): TutorialsPoint?java8
MIME字符串 :ff3eb049-2440-4776-ba6d-becccda60c6f5def99b1-2009-433b-a09c-7fc393305e0641629364-0a92-4d5e-8c5d-1c5ad6a14025ec2ad8ce-2a51-4a0e-b633-ddbb9b2671a15a4fe3e9-7217-4209-a2f1-c478f29cf2dc591579bb-5e31-4984-b4c2-a960924e06e125b28902-aea3-4f76-bcd2-afe533a65cccb66a5eda-71e4-46ba-93fa-0ce685e7e67b9f704c87-34a0-441c-88fc-867a861d771d450d445d-a7ef-4309-b884-f787615f0512
MIME(编码) :ZmYzZWIwNDktMjQ0MC00Nzc2LWJhNmQtYmVjY2NkYTYwYzZmNWRlZjk5YjEtMjAwOS00MzNiLWEw
OWMtN2ZjMzkzMzA1ZTA2NDE2MjkzNjQtMGE5Mi00ZDVlLThjNWQtMWM1YWQ2YTE0MDI1ZWMyYWQ4
Y2UtMmE1MS00YTBlLWI2MzMtZGRiYjliMjY3MWExNWE0ZmUzZTktNzIxNy00MjA5LWEyZjEtYzQ3
OGYyOWNmMmRjNTkxNTc5YmItNWUzMS00OTg0LWI0YzItYTk2MDkyNGUwNmUxMjViMjg5MDItYWVh
My00Zjc2LWJjZDItYWZlNTMzYTY1Y2NjYjY2YTVlZGEtNzFlNC00NmJhLTkzZmEtMGNlNjg1ZTdl
NjdiOWY3MDRjODctMzRhMC00NDFjLTg4ZmMtODY3YTg2MWQ3NzFkNDUwZDQ0NWQtYTdlZi00MzA5
LWI4ODQtZjc4NzYxNWYwNTEy
MIME(解码): ff3eb049-2440-4776-ba6d-becccda60c6f5def99b1-2009-433b-a09c-7fc393305e0641629364-0a92-4d5e-8c5d-1c5ad6a14025ec2ad8ce-2a51-4a0e-b633-ddbb9b2671a15a4fe3e9-7217-4209-a2f1-c478f29cf2dc591579bb-5e31-4984-b4c2-a960924e06e125b28902-aea3-4f76-bcd2-afe533a65cccb66a5eda-71e4-46ba-93fa-0ce685e7e67b9f704c87-34a0-441c-88fc-867a861d771d450d445d-a7ef-4309-b884-f787615f0512
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2、摘要算法
摘要算法主要分为MD，SHA和Hmac算法（已经被攻破，彩虹表和MD5站点）。摘要算法其实是用于效验数据完整性的，我们在下载某些文件时，会有MD5和SHA1值提供我们校验下载的文件是否完整，可以用于根据数据生成其唯一的摘要值，无法根据摘要值知道原数据，属于不可逆的。
原理：摘要由一个单向Hash加密函数对消息进行作用而产生，HASH函数的抗冲突性使得如果一段明文稍有变化，哪怕只更改该段落的一个字母，通过哈希算法作用后都将产生不同的值。而HASH算法的单向性使得要找到哈希值相同的两个不同的输入消息，在计算上是不可能的。所以数据的哈希值，即消息摘要，可以检验数据的完整性。
主要过程如下：
1、以上是坏蛋不知密钥情况下，发送请求，第三方根据请求参数+密钥生成sign与请求的sign比较；
2、而如果坏蛋通过截获的sign，解密md5获得明文，并且通过大量的请求分析出密钥与消息体的拼接规则，则依然存在安全问题；
注意：这里128位是二进制，换算16进制32位
package com.paic.java8;
import org.apache.commons.codec.binary.Hex;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class MDXDemo {
    public static void main(String[] args) {
        String screctKey = "123";
        String content = "Hello";
        encrypt(content,screctKey);
     * @param content
     * @param screctKey
    public static void encrypt(String content,String screctKey){
        MessageDigest md5= null;
        MessageDigest md2= null;
        //内容 + 密钥
        //原因：如果单单只是内容，攻击方也是可以通过MD5得到sign1，拼接攻击方不知到的密钥，在攻击方篡改内容后将得到不同的sign2
        //当然攻击方可以根据sign1解密从而获得密钥
        String src = content + screctKey;
        try {
            md5 = MessageDigest.getInstance("MD5");
            md2 = MessageDigest.getInstance("MD2");
            byte[] digest5 = md5.digest(src.getBytes());
            byte[] digest2 = md2.digest(src.getBytes());
            System.out.println("JDK MD5: "+ Hex.encodeHexString(digest5));
            System.out.println("JDK MD2: "+ Hex.encodeHexString(digest2));
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
32位字符
JDK MD5: d0aabe9a362cb2712ee90e04810902f3
JDK MD2: 014b1eb8d5557bb786b83a18c9fbbe2e
解密，在线上测试下：https://www.somd5.com/
 安全性：SHA1所产生的摘要比MD5长32位。若两种散列函数在结构上没有任何问题的话，SHA1比MD5更安全
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class SHAXDemo {
    public static void main(String[] args) {
        String content = "Hello";
        jdkSHA1(content);
        ccsha(content);
     * JDK实现方式（同样是使用MessageDigest）
     * @param src
    public static void jdkSHA1(String src){
        MessageDigest digest;
        try {
            digest = MessageDigest.getInstance("SHA");
            digest.update(src.getBytes());
            System.out.println("JDK SHA1:"+Hex.encodeHexString(digest.digest()));
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
     * cc的实现方式
     * @param src
    public static void ccsha(String src){
        System.out.println("CC  SHA1:"+ DigestUtils.sha1Hex(src));
    //BC略...
JDK SHA1:f7ff9e8b7bb2e09b70935a5d785e0cc5d9d0abf0
CC   SHA1:f7ff9e8b7bb2e09b70935a5d785e0cc5d9d0abf0
含有密钥的摘要算法，也有简称mac，密钥不同摘要也不同

package com.paic.java8.encry;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
public class HmacDemo {
    public static void main(String[] args) {
        encrypt("Hello","aaaaaaaaaa");
     * JDK的实现方式  BC略
     * @param content
     * @param key
    public static void encrypt(String content,String key){
        SecretKey secretKey = getSecretKey(key);
        try {
            Mac mac= Mac.getInstance(secretKey.getAlgorithm());
            //初始化mac
            mac.init(secretKey);
            byte[] hmacMD5Bytes=mac.doFinal(content.getBytes());
            //jdk hmacMD5: bfb61695a42d5d16add45743a4e0eea4
            System.out.println("jdk hmacMD5: "+Hex.encodeHexString(hmacMD5Bytes));
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
     * 获取默认密钥
     * @return
    public static SecretKey getDefaultSecretKey() {
        SecretKey secretKey = null;
        //初始化KeyGenerator




    

        KeyGenerator keyGenerator = null;
        try {
            keyGenerator = KeyGenerator.getInstance("HmacMD5");
            //产生密钥
            secretKey = keyGenerator.generateKey();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        return secretKey;
     * 自定义密钥
     * @param key
     * @return
    public static SecretKey getSecretKey(String key){
        SecretKey secretKey = null;
        byte[] keyByteArr= null;
        try {
            //长度必须偶数
            boolean flag = (null == key)? true : ((key.length()) & 1) != 0;
            if(flag){
                throw new DecoderException("Key长度必须偶数");
            keyByteArr = Hex.decodeHex(key.toCharArray());
            secretKey = new SecretKeySpec(keyByteArr,"HmacMD5");
        } catch (DecoderException e) {
            e.printStackTrace();
        return secretKey;
     * BC方式
    public static void bcHmacMd5(){
        String src = "Hello,World";
        HMac hMac=new HMac(new MD5Digest());
        hMac.init(new KeyParameter(org.bouncycastle.util.encoders.Hex.decode("aaaaaaaaaa")));  //需要十位密钥
        hMac.update(src.getBytes(),0,src.getBytes().length);
        byte[] hmacMD5=new byte[hMac.getMacSize()];
        hMac.doFinal(hmacMD5, 0);
        System.out.println("bc hmacMD5: "+org.bouncycastle.util.encoders.Hex.toHexString(hmacMD5));
3、对称加密
所谓对称是说发送方和接收方的密钥是一样的,因为密钥一样所以安全性跟非对称比较来说就不太安全了。
package com.paic.java8.encry;
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import javax.crypto.*;
import javax.crypto.spec.DESKeySpec;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.Security;
import java.security.spec.InvalidKeySpecException;
public class DesSemo {
    public static void main(String[] args) {
        //jdkDES加密: cfa7121606a4413138d8d3781afeaa1c
        try {
            SecretKey key = getSecretKey("aaaabbbbcc");
            byte[] content = jdkDESEncrypt("Hello DES", key);
            jdkDESDecrypt(content, key);
            bcDES();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
    public static SecretKey getDefaultSecretKey() {
        KeyGenerator keyGenerator = null;
        SecretKey secretKey = null;
        try {
            keyGenerator = KeyGenerator.getInstance("DES");
            keyGenerator.init(56);      //指定key长度，同时也是密钥长度(56位)
            secretKey = keyGenerator.generateKey(); //生成key的材料
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        return secretKey;
     * key 长度 > 8
     * @param key
     * @return
     * @throws InvalidKeyException
    public static SecretKey getSecretKey(String key) throws InvalidKeyException {
        SecretKey secretKey = null;
        byte[] keyByteArr = key.getBytes();
        if (keyByteArr.length - 0 < 8) {
            throw new InvalidKeyException("Wrong key size");
        DESKeySpec desKeySpec = null;
        try {
            desKeySpec = new DESKeySpec(keyByteArr);
            SecretKeyFactory factory = SecretKeyFactory.getInstance("DES");
            secretKey = factory.generateSecret(desKeySpec);
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        return secretKey;
     * DES 加密
     * @param content
     * @param key2
    public static byte[] jdkDESEncrypt(String content, SecretKey key2) {
        //加密
        Cipher cipher = null;
        byte[] result = null;
        try {
            //算法类型/工作方式/填充方式
            cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
            //指定为加密模式
            cipher.init(Cipher.ENCRYPT_MODE, key2);
            result = cipher.doFinal(content.getBytes());
            //转换为十六进制
            //desResult = Hex.encodeHexString(result);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        return result;
     * @param encrypt
     * @param key
    public static void jdkDESDecrypt(byte[] encrypt, SecretKey key) {
        Cipher cipher = null;
        try {
            cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
            //解密
            cipher.init(Cipher.DECRYPT_MODE, key);  //相同密钥，指定为解密模式
            byte[] result = cipher.doFinal(encrypt);   //根据加密内容解密
            System.out.println("jdkDES解密: " + new String(result));  //转换字符串
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
     * BC方式
    public static void bcDES(){
        String src = "Hello DES";
        try {
            //通过改变provider的方式
            Security.addProvider(new BouncyCastleProvider());
            //生成key,使用bc需要在后面指定"BC"
            KeyGenerator keyGenerator=KeyGenerator.getInstance("DES","BC");
            keyGenerator.getProvider();
            keyGenerator.init(56);      //指定key长度，同时也是密钥长度
            SecretKey secretKey = keyGenerator.generateKey(); //生成key的材料
            byte[] key = secretKey.getEncoded();  //生成key
            //key转换成密钥
            DESKeySpec desKeySpec=new DESKeySpec(key);
            SecretKeyFactory factory=SecretKeyFactory.getInstance("DES");
            SecretKey key2 = factory.generateSecret(desKeySpec);      //转换后的密钥
            //加密
            Cipher cipher=Cipher.getInstance("DES/ECB/PKCS5Padding");  //算法类型/工作方式/填充方式
            cipher.init(Cipher.ENCRYPT_MODE, key2);
            byte[] result=cipher.doFinal(src.getBytes());
            System.out.println("bcDES加密: "+Hex.encodeHexString(result));  //转换为十六进制
            //解密
            cipher.init(Cipher.DECRYPT_MODE,key2);  //相同密钥
            result = cipher.doFinal(result);   //根据加密内容解密
            System.out.println("bcDES解密: "+new String(result));  //转换字符串
        } catch (Exception e) {
            e.printStackTrace();
package com.paic.java8.encry;
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import java.security.SecureRandom;
import java.security.Security;
public class Des3Demo {
    private static String src="Hello 3DES";
    public static void main(String[] args) {
     * jdk方式
    public static void jdkDES(){
        try {
            //生成key
            KeyGenerator keyGenerator=KeyGenerator.getInstance("DESede");
            //keyGenerator.init(112);      //3DES需要112 or 168位
            keyGenerator.init(new SecureRandom());   //或者使用这种方式默认长度，无需指定长度
            SecretKey secretKey = keyGenerator.generateKey(); //生成key的材料
            byte[] key = secretKey.getEncoded();  //生成key
            //key转换成密钥
            DESedeKeySpec desKeySpec=new DESedeKeySpec(key);
            SecretKeyFactory factory=SecretKeyFactory.getInstance("DESede");
            SecretKey key2 = factory.generateSecret(desKeySpec);      //转换后的密钥
            //加密
            Cipher cipher=Cipher.getInstance("DESede/ECB/PKCS5Padding");  //算法类型/工作方式/填充方式
            cipher.init(Cipher.ENCRYPT_MODE, key2);   //指定为加密模式
            byte[] result=cipher.doFinal(src.getBytes());
            System.out.println("jdk3DES加密: "+ Hex.encodeHexString(result));  //转换为十六进制
            //解密
            cipher.init(Cipher.DECRYPT_MODE,key2);  //相同密钥，指定为解密模式
            result = cipher.doFinal(result);   //根据加密内容解密
            System.out.println("jdk3DES解密: "+new String(result));  //转换字符串
        } catch (Exception e) {
            e.printStackTrace();
     * BC方式
    public static void bcDES(){
        try {
            //通过改变provider的方式，其他操作一样
            Security.addProvider(new BouncyCastleProvider());
            //生成key
            KeyGenerator keyGenerator=KeyGenerator.getInstance("DESede");
            keyGenerator.init(new SecureRandom());
            SecretKey secretKey = keyGenerator.generateKey(); //生成key的材料
            byte[] key = secretKey.getEncoded();  //生成key
            //key转换成密钥
            DESedeKeySpec desKeySpec=new DESedeKeySpec(key);
            SecretKeyFactory factory=SecretKeyFactory.getInstance("DESede");
            SecretKey key2 = factory.generateSecret(desKeySpec);      //转换后的密钥
            //加密
            Cipher cipher=Cipher.getInstance("DESede/ECB/PKCS5Padding");  //算法类型/工作方式/填充方式
            cipher.init(Cipher.ENCRYPT_MODE, key2);   //指定为加密模式
            byte[] result=cipher.doFinal(src.getBytes());
            System.out.println("jdk3DES加密: "+Hex.encodeHexString(result));  //转换为十六进制
            //解密
            cipher.init(Cipher.DECRYPT_MODE,key2);  //相同密钥，指定为解密模式
            result = cipher.doFinal(result);   //根据加密内容解密
            System.out.println("jdk3DES解密: "+new String(result));  //转换字符串
        } catch (Exception e) {
            e.printStackTrace();
4、非对称加密