Web应用加密数据传输方案

概述

最初的方案

改进后的方案

秘钥的过期时间

概述

介于公司最近发布了一个面向C端用户的Web系统，为防止前端调用后端的API接口时，数据传输的内容轻易的被黑客获取，而设计的一个前后端数据加密传输方案

最初的方案

在最开始，我们采用了最传统的AES对称加密的方式来加密API数据，前后端共用一个秘钥。具体操作流程为前端用秘钥将请求报文加密后发送到后端，后端在过滤器中同一个秘钥来完成解密请求报文；后端在响应阶段采用同一个秘钥对想用报文加密后发送到前端，前端收到响应报文后完成响应报文的解密。但是这样做有一个非常明显的弊端，就是前端需要将这个秘钥在前端的代码中写死，一旦黑客在浏览器中打开F12搜索关键词 AES，很容易找我们设置的秘钥，从而导致整个加解密全部暴露。

改进后的方案

为解决秘钥容易在前端暴露的问题，我们重新设计了整个加解密的流程，整个过程使用了两对RAS非对称加密的秘钥。一对给前端加密、后端解密用(后端秘钥)，另一对给后端加密，前端解密用(前端秘钥)。具体为：

1. 前端在加载主页时，以伪装成加载图片内容(base64字符串)的形式先向后端发送两个请求，分别用于获取前段解密用的私钥、加密用的公钥以及秘钥对应的摘要。注意，这里分别获取的公钥、私钥并不是同一对，而是两对秘钥中分别取一个。返回的秘钥伪装成一个base64格式的图片流，并且使用了一定的扰动处理。

@Operation(summary = "获取公钥")@GetMapping("/welcome")public RespEntity<String> welcome() throws Exception {String s1 = GlobalStatus.getRequest().getHeader("s1");String publicKey = "";if(StringUtils.isNotBlank(s1)){publicKey = rsaService.getPublicKey(CodecProperties.SERVER_RSA_KEY_PRE,s1);if(StringUtils.isBlank(publicKey)){return RespEntity.ok();}}else{// 生成一对公私钥Map<String, String> keyMap = rsaService.getRsa(CodecProperties.SERVER_RSA_KEY_PRE,s1);publicKey = keyMap.get(RsaUtils.PUBLIC_KEY);s1 =  Sha1Utils.getSHA1Digest(publicKey);}// 将秘钥进行混淆后拼上摘要后返回前端String firstStr = publicKey.substring(0,3);String secondStr = publicKey.substring(3,publicKey.length()-3);String thirdStr = publicKey.substring(publicKey.length()-3);String simulatePublicKey = StringUtils.getRandomLetterString(3) +  thirdStr + secondStr + firstStr + "_" + s1 + StringUtils.getRandomLetterString(4);byte [] simulatePublicKeyArray = simulatePublicKey.getBytes();String keyBase64 = "data:image/png;base64," + Base64.getEncoder().encodeToString(simulatePublicKeyArray);return RespEntity.ok(keyBase64);}@Operation(summary = "获取私钥")@PostMapping("/getUsefulImg")public RespEntity<String> getUsefulImg() throws Exception {String s2 = GlobalStatus.getRequest().getHeader("s2");String privateKey = "";if(StringUtils.isNotBlank(s2)){privateKey = rsaService.getPrivateKey(CodecProperties.CLIENT_RSA_KEY_PRE,s2);if(StringUtils.isBlank(privateKey)){return RespEntity.ok();}}else{// 生成一对公私钥Map<String, String> keyMap = rsaService.getRsa(CodecProperties.CLIENT_RSA_KEY_PRE,s2);privateKey = keyMap.get(RsaUtils.PRIVATE_KEY);String publicKey = keyMap.get(RsaUtils.PUBLIC_KEY);s2 =  Sha1Utils.getSHA1Digest(publicKey);}// 将秘钥进行混淆后拼上摘要后返回前端String firstStr = privateKey.substring(0,privateKey.indexOf("/"));String secondStr = privateKey.substring(privateKey.indexOf("/"),privateKey.lastIndexOf("/")+1);String thirdStr = privateKey.substring(privateKey.lastIndexOf("/")+1);String simulatePrivateKey = StringUtils.getRandomLetterString(3) +  thirdStr + secondStr + firstStr + "_" + s2 + StringUtils.getRandomLetterString(4);byte [] simulatePrivateKeyArray = simulatePrivateKey.getBytes();String keyBase64 = "data:image/png;base64," + Base64.getEncoder().encodeToString(simulatePrivateKeyArray);return RespEntity.ok(keyBase64);}

2. 考虑到RSA非对称加密的性能较差，因此对报文内容的加密我们仍然使用AES对称加密，前端每次在加密请求报文时，会生成一对新的AES秘钥，对请求报文加密，然后使用获取到的RAS非对称加密的私钥对这个AES的key做加密；那么请求报文中，将会有加密后的data、私钥的摘要、公钥的摘要、加密的AES的key发送给后端。

3. 后端在收到请求报文后，根据私钥的摘要找到对应私钥的公钥，然后以公钥对加密的AES key进行解密，然后再以AES的key对请求报文进行解密。

4. 后端在加密响应报文时，同样的会生成一对新的AES的key，以这个key对响应报文加密，然后以后端的私钥对AES key 加密；因此，后端的响应报文也会有加密后的data、私钥的摘要、加密的AES的key三个字段。

5. 前端在收到响应报文后，先根据摘要校验后端加密的公钥与前端解密的私钥是否是一对，如果不是，则要重新获取新的私钥。

package com.vteam.uap.core.filter;import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONObject;
import com.vteam.uap.cache2.strategy.HashMapContainer;
import com.vteam.uap.cache2.strategy.StringContainer;
import com.vteam.uap.common.util.*;
import com.vteam.uap.core.service.RsaService;
import com.vteam.uap.jwt.exception.ParamCheckException;
import com.vteam.uap.security.codec.CodecProperties;
import com.vteam.uap.security.global.SecurityGlobalStatus;
import com.vteam.uap.security.httpWrapper.RequestWrapper;
import com.vteam.uap.security.httpWrapper.ResponseWrapper;
import com.vteam.uap.util.SpringContextUtils;
import jakarta.annotation.Resource;
import jakarta.servlet.Filter;
import jakarta.servlet.*;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.ArrayUtils;
import org.springframework.util.PatternMatchUtils;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.HandlerExceptionResolver;import java.io.IOException;
import java.util.Map;
import java.util.Objects;/*** @author Miller.Lai* @description:  加解码过滤器* @date 2023-12-15 16:46:03*/
@Slf4j
public class CodecFilter implements Filter {@Resourceprotected CodecProperties codecProperties;@Resourceprivate StringContainer stringContainer;@Resourceprivate HashMapContainer hashMapContainer;@Resourceprivate RsaService rsaService;@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {// 请求解密if (codecProperties.isApiEnable() && !isIgnore()  &&(( "POST".equalsIgnoreCase(((HttpServletRequest)request).getMethod().trim()) && "application/json".equals(request.getContentType().trim().toLowerCase()))|| !"POST".equalsIgnoreCase(((HttpServletRequest)request).getMethod().trim())) ){// 包装响应对象ResponseWrapper responseWrapper = new ResponseWrapper((HttpServletResponse) response);String url = ((HttpServletRequest) request).getRequestURI();String userId = SecurityGlobalStatus.getUserid();HandlerExceptionResolver handlerExceptionResolver = (HandlerExceptionResolver) SpringContextUtils.getBean("handlerExceptionResolver");// 如果是post请求，则请求体解密，get请求不做处理if("POST".equals(((HttpServletRequest)request).getMethod().trim().toUpperCase())){RequestWrapper requestWrapper = new RequestWrapper((HttpServletRequest) request);String bodyStr =  requestWrapper.getRequestBody();if(StringUtils.isNotBlank(bodyStr)){JSONObject bodyJson = JSONObject.parseObject(bodyStr);Object data = bodyJson.get("data");// s1是服务端秘钥的摘要String s1 = ((HttpServletRequest) request).getHeader("s1");if(StringUtils.isEmpty(s1)){log.error("服务端秘钥摘要缺失，需要添加请求头：s1");handlerExceptionResolver.resolveException((HttpServletRequest) request,(HttpServletResponse) response,null,new ParamCheckException("非法请求"));return;}// 从请求参数 uuid 中拿到 AES解密的 key 和 ivString cryptUuid = (String)bodyJson.get("u");if( StringUtils.isBlank(cryptUuid) ){log.error("加密的k、v缺失，body中必须要有u字段");handlerExceptionResolver.resolveException((HttpServletRequest) request,(HttpServletResponse) response,null,new ParamCheckException("非法请求"));return;}String privateKey = rsaService.getPrivateKey(CodecProperties.SERVER_RSA_KEY_PRE,s1);if(StringUtils.isBlank(privateKey)){log.error("未找到s1对应的秘钥信息");handlerExceptionResolver.resolveException((HttpServletRequest) request,(HttpServletResponse) response,null,new ParamCheckException("非法请求"));return;}String k = null;String v = null;try{String uuid = RsaUtils.privateDecrypt(cryptUuid, privateKey);String[] uuidArray = uuid.split("_");k = uuidArray[0];v = uuidArray[1];}catch (Exception e){log.error("AES的k、v解密失败");handlerExceptionResolver.resolveException((HttpServletRequest) request,(HttpServletResponse) response,null,new ParamCheckException("非法请求"));return;}if(data instanceof String && !((String) data).trim().isEmpty()){if (log.isDebugEnabled()) {log.debug("解密 API 请求消息：type={}, requestBody={}",requestWrapper.getMethod(), bodyJson.toJSONString());}String plainText = AesUtils.decrypt((String) data, AesUtils.Mode.API,k,v,codecProperties.isDbEnable());Object dataObj = "";try{dataObj = JSON.parseObject(plainText);Object timestampObj = ((JSONObject)dataObj).get("timestamp");if(timestampObj == null ){log.error("请求时间戳缺失");handlerExceptionResolver.resolveException((HttpServletRequest) request,(HttpServletResponse) response,null,new ParamCheckException("非法请求"));return;}long timestamp = (long)timestampObj;long currentTimeMillis = System.currentTimeMillis();long currentTimeMicros = currentTimeMillis * 1000;// 请求时间戳是否过期，超过1分钟过期if((currentTimeMicros -timestamp)/(1000 * 1000)>60){log.error("请求时间戳过期");handlerExceptionResolver.resolveException((HttpServletRequest) request,(HttpServletResponse) response,null,new ParamCheckException("非法请求"));return;}boolean ifAbsent = stringContainer.setIfAbsent(MD5Utils.getDigest(userId + url + timestamp), "1", 61L);if(!ifAbsent){log.error("当前请求已被处理过，二次请求不再受理");handlerExceptionResolver.resolveException((HttpServletRequest) request,(HttpServletResponse) response,null,new ParamCheckException("非法请求"));return;}}catch (Exception e1){try {dataObj = JSON.parseArray(plainText);}catch (Exception e2){dataObj = data + "";}}bodyJson.put("data",dataObj);requestWrapper.setRequestBody(bodyJson.toJSONString());}else if(data != null && !(data instanceof String)){log.error("服务已开启请求参数加密处理，但当前请求参数未被加密");handlerExceptionResolver.resolveException((HttpServletRequest) request,(HttpServletResponse) response,null,new ParamCheckException("非法请求"));return;}}chain.doFilter(requestWrapper, responseWrapper);}else{chain.doFilter(request, responseWrapper);}// 拿到响应对象byte[] responseData = responseWrapper.getResponseData();String contentType = responseWrapper.getContentType();if(contentType != null && "application/json".equalsIgnoreCase(contentType.trim())){String originalResulet = new String(responseData);JSONObject jsonObject  =JSONObject.parseObject(originalResulet);// 拿到响应对象中的dataObject data = jsonObject.get("data");if(data != null){// AES 加密String k = StringUtils.getRandomString(16);String v = StringUtils.getRandomString(16);String encText = AesUtils.encrypt(JSON.toJSONString(data), AesUtils.Mode.API,k,v,codecProperties.isDbEnable());// s2 是服务端秘钥的摘要String s2 = ((HttpServletRequest) request).getHeader("s2");if( s2 == null){log.error("服务端秘钥的摘要缺失，需要添加请求头：s2 ");handlerExceptionResolver.resolveException((HttpServletRequest) request,(HttpServletResponse) response,null,new ParamCheckException("非法请求"));return;}String publicKey = (String)hashMapContainer.doQueryCache(CodecProperties.CLIENT_RSA_KEY_PRE + s2,RsaUtils.PUBLIC_KEY);if(publicKey == null){Map<String,String> clientRsa = rsaService.getRsa(CodecProperties.CLIENT_RSA_KEY_PRE,s2);publicKey = clientRsa.get(RsaUtils.PUBLIC_KEY);s2 = clientRsa.get(RsaUtils.SignMode.SHA1.getMode());}String aeskv = RsaUtils.publicEncrypt(k + "_" + v,publicKey);jsonObject.put("data", encText);jsonObject.put("u",aeskv);jsonObject.put("s2",s2);}responseData = jsonObject.toJSONString().getBytes("utf-8");}HttpServletResponse httpServletResponse = (HttpServletResponse) response;response.setContentLength(responseData.length);httpServletResponse.getOutputStream().write(responseData);httpServletResponse.getOutputStream().flush();}else{// 处理业务逻辑chain.doFilter(request, response);}}@Overridepublic void destroy() {}protected boolean isIgnore() {boolean isIgnore = false;String[] ignoreUrl = codecProperties.getIgnoreUrl();if (ArrayUtils.isNotEmpty(ignoreUrl)) {HttpServletRequest request =((ServletRequestAttributes) Objects.requireNonNull(RequestContextHolder.getRequestAttributes())).getRequest();for (String s : ignoreUrl) {if (PatternMatchUtils.simpleMatch(s, request.getRequestURI())) {isIgnore = true;break;}}}return isIgnore;}public static void main(String[] args) {int timestampObj = (int)230416900;long timestamp =timestampObj;}
}