RSA算法加密解密，数据传输，前台与后台数据交互

Posted 2021-12-28 thinksep

1、RSA算法加密解密思路。

      java后台随机生成公钥、私钥。存储于session中，告知前台js获取公钥。通过jsencrypt.min.js进行加密。传输回后台，后台通过私钥解密。

2、RSA常见异常分解。

    问题一

Cannot find any provider supporting RSA

出现此问题，属于JDK版本bug问题，笔者1.8.0_171遇到此问题，更换1.8.0_211之后即可解决。

问题二

DER input, Integer tag error

出现此问题，主要是公钥，私钥混用到至，通过断点发现解密时，用的公钥进行解密，哈哈。

问题三

Decryption error

出现此问题，主要是前台页面传参至后台，出现“+”符号被替换成“ ”空格导致无法进行解密。

 

3.代码部分。

引用地址：https://blog.csdn.net/qq_36827957/article/details/81563973 

<script language=javascript>
var publicKey = ‘<%=session.getAttribute("publicKey")%>‘;
$(document).ready(function() 
    $(‘#doSearch‘).click(function(e) 
        var  phoneNo= $("#phoneNo").val();
        var encrypt = new JSEncrypt();
        encrypt.setPublicKey(publicKey);
        phoneNo = encrypt.encrypt(phoneNo);
        alert(phoneNo);
        document.frm.submit();
    );
);    
</script>

 放入session部分

    @RequestMapping(value = "/index")
    public String login(Model model, HttpSession session,HttpServletRequest request) 
        Map<String, String> rsaMap = new  HashMap<String, String>();
        rsaMap = RsaUtil.createRSAKeys();
        String publicKey = rsaMap.get("publicKey");
        String privateKey = rsaMap.get("privateKey");
        session.setAttribute("publicKey", publicKey);
        session.setAttribute("niceKey", privateKey);
        return "index";
    

 

 解析部分

    @RequestMapping(value = "/search", method = RequestMethod.POST)
    public String search(@ModelAttribute String phoneNo, HttpServletRequest request,
            HttpSession session, Model model) 
                if (phoneNo==null || "".equals(phoneNo)) 
                    model.addAttribute("returnUrl", "fail");
                    return "fail";
                
                //RSA解密
                phoneNo = phoneNo.replace(" ", "+");
                phoneNo = RsaUtil.decode(phoneNo, session.getAttribute("niceKey").toString());
                System.out.println("phoneNo:" + phoneNo);
                
                
                    //业务代码
                
        return "success";
    

 

 

 

 RSA工具类部分

package com.thinksep.utils;

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
 
import javax.crypto.Cipher;
 
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.tomcat.util.codec.binary.Base64;
 
/**
* @author 
* @createDate 
*/
public class RsaUtil 
    protected static final Log log = LogFactory.getLog(RsaUtil.class);
    private static String KEY_RSA_TYPE = "RSA";
    private static int KEY_SIZE = 1024;//JDK方式RSA加密最大只有1024位
    private static int ENCODE_PART_SIZE = KEY_SIZE/8;
    public static final String PUBLIC_KEY_NAME = "public";
    public static final String PRIVATE_KEY_NAME = "private";
 
    /**
     * 创建公钥秘钥
     * @return
     */
    public static Map<String,String> createRSAKeys()
        Map<String,String> keyPairMap = new HashMap<>();//里面存放公私秘钥的Base64位加密
        try 
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(KEY_RSA_TYPE);
            keyPairGenerator.initialize(KEY_SIZE,new SecureRandom());
            KeyPair keyPair = keyPairGenerator.generateKeyPair();
 
            //获取公钥秘钥
            String publicKeyValue = Base64.encodeBase64String(keyPair.getPublic().getEncoded());
            String privateKeyValue = Base64.encodeBase64String(keyPair.getPrivate().getEncoded());
 
            //存入公钥秘钥，以便以后获取
            keyPairMap.put(PUBLIC_KEY_NAME,publicKeyValue);
            keyPairMap.put(PRIVATE_KEY_NAME,privateKeyValue);
         catch (NoSuchAlgorithmException e) 
            log.error("当前JDK版本没找到RSA加密算法！");
            e.printStackTrace();
        
        return keyPairMap;
    
 
    /**
     * 公钥加密
     * 描述：
     *     1字节 = 8位；
     *     最大加密长度如 1024位私钥时，最大加密长度为 128-11 = 117字节，不管多长数据，加密出来都是 128 字节长度。
     * @param sourceStr
     * @param publicKeyBase64Str
     * @return
     */
    public static String encode(String sourceStr,String publicKeyBase64Str)
        byte [] publicBytes = Base64.decodeBase64(publicKeyBase64Str);
        //公钥加密
        X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(publicBytes);
        List<byte[]> alreadyEncodeListData = new LinkedList<>();
 
        int maxEncodeSize = ENCODE_PART_SIZE - 11;
        String encodeBase64Result = null;
        try 
            KeyFactory keyFactory = KeyFactory.getInstance(KEY_RSA_TYPE);
            PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            Cipher cipher = Cipher.getInstance(KEY_RSA_TYPE);
            cipher.init(Cipher.ENCRYPT_MODE,publicKey);
            byte[] sourceBytes = sourceStr.getBytes("utf-8");
            int sourceLen = sourceBytes.length;
            for(int i=0;i<sourceLen;i+=maxEncodeSize)
                int curPosition = sourceLen - i;
                int tempLen = curPosition;
                if(curPosition > maxEncodeSize)
                    tempLen = maxEncodeSize;
                
                byte[] tempBytes = new byte[tempLen];//待加密分段数据
                System.arraycopy(sourceBytes,i,tempBytes,0,tempLen);
                byte[] tempAlreadyEncodeData = cipher.doFinal(tempBytes);
                alreadyEncodeListData.add(tempAlreadyEncodeData);
            
            int partLen = alreadyEncodeListData.size();//加密次数
 
            int allEncodeLen = partLen * ENCODE_PART_SIZE;
            byte[] encodeData = new byte[allEncodeLen];//存放所有RSA分段加密数据
            for (int i = 0; i < partLen; i++) 
                byte[] tempByteList = alreadyEncodeListData.get(i);
                System.arraycopy(tempByteList,0,encodeData,i*ENCODE_PART_SIZE,ENCODE_PART_SIZE);
            
            encodeBase64Result = Base64.encodeBase64String(encodeData);
         catch (Exception e) 
            e.printStackTrace();
        
        return encodeBase64Result;
    
 
    /**
     * 私钥解密
     * @param sourceBase64RSA
     * @param privateKeyBase64Str
     */
    public static String decode(String sourceBase64RSA,String privateKeyBase64Str)
        byte[] privateBytes = Base64.decodeBase64(privateKeyBase64Str);
        byte[] encodeSource = Base64.decodeBase64(sourceBase64RSA);
        int encodePartLen = encodeSource.length/ENCODE_PART_SIZE;
        List<byte[]> decodeListData = new LinkedList<>();//所有解密数据
        String decodeStrResult = null;
        //私钥解密
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(privateBytes);
        try 
            KeyFactory keyFactory = KeyFactory.getInstance(KEY_RSA_TYPE);
            PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
            Cipher cipher = Cipher.getInstance(KEY_RSA_TYPE);
            cipher.init(Cipher.DECRYPT_MODE,privateKey);
            int allDecodeByteLen = 0;//初始化所有被解密数据长度
            for (int i = 0; i < encodePartLen; i++) 
                byte[] tempEncodedData = new byte[ENCODE_PART_SIZE];
                System.arraycopy(encodeSource,i*ENCODE_PART_SIZE,tempEncodedData,0,ENCODE_PART_SIZE);
                byte[] decodePartData = cipher.doFinal(tempEncodedData);
                decodeListData.add(decodePartData);
                allDecodeByteLen += decodePartData.length;
            
            byte [] decodeResultBytes = new byte[allDecodeByteLen];
            for (int i = 0,curPosition = 0; i < encodePartLen; i++) 
                byte[] tempSorceBytes = decodeListData.get(i);
                int tempSourceBytesLen = tempSorceBytes.length;
                System.arraycopy(tempSorceBytes,0,decodeResultBytes,curPosition,tempSourceBytesLen);
                curPosition += tempSourceBytesLen;
            
            decodeStrResult = new String(decodeResultBytes,"UTF-8");
        catch (Exception e)
            e.printStackTrace();
        
        return decodeStrResult;