概述

今天这篇文章聊一聊接口安全问题，涉及到接口的加密、解密。

接口数据加解密流程图

涉及客户端和服务端的整体改造，可以在接口统一加 /secret/ 前缀来区分。

代码Demo

用户类型：

@Data
public class User {
    private Integer id;
    private String name;
    private UserType userType = UserType.COMMON;
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private LocalDateTime registerTime;
}

用户类型枚举类：

@Getter
@JsonFormat(shape = JsonFormat.Shape.OBJECT)
public enum UserType {
    VIP("VIP用户"),
    COMMON("普通用户");
    private String code;
    private String type;

    UserType(String type) {
        this.code = name();
        this.type = type;
    }
}

构造一个简单的用户列表查询示例：

@RestController
@RequestMapping(value = {"/user", "/secret/user"})
public class UserController {
    @RequestMapping("/list")
    ResponseEntity<List<User>> listUser() {
        List<User> users = new ArrayList<>();
        User u = new User();
        u.setId(1);
        u.setName("boyka");
        u.setRegisterTime(LocalDateTime.now());
        u.setUserType(UserType.COMMON);
        users.add(u);
        ResponseEntity<List<User>> response = new ResponseEntity<>();
        response.setCode(200);
        response.setData(users);
        response.setMsg("用户列表查询成功");
        return response;
    }
}

查询结果如下：

{
 "code": 200,
 "data": [{
  "id": 1,
  "name": "boyka",
  "userType": {
   "code": "COMMON",
   "type": "普通用户"
  },
  "registerTime": "2022-03-24 23:58:39"
 }],
 "msg": "用户列表查询成功"
}

加解密拦截器

目前主要是利用ControllerAdvice来对请求和响应体进行拦截，主要定义SecretRequestAdvice对请求进行加密和SecretResponseAdvice对响应进行加密(实际情况会稍微复杂一点，项目中又GET类型请求，自定义了一个Filter进行不同的请求解密处理)。
网上的ControllerAdvice使用示例非常多，这把两个核心方法给大家展示看看。

SecretRequestAdvice请求解密

@ControllerAdvice
@Order(Ordered.HIGHEST_PRECEDENCE)
@Slf4j
public class SecretRequestAdvice extends RequestBodyAdviceAdapter {
    @Override
    public boolean supports(MethodParameter methodParameter, Type type, Class<? extends HttpMessageConverter<?>> aClass) {
        return true;
    }

    @Override
    public HttpInputMessage beforeBodyRead(HttpInputMessage inputMessage, MethodParameter parameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) throws IOException {
        //如果支持加密消息，进行消息解密。
        String httpBody;
        if (Boolean.TRUE.equals(SecretFilter.secretThreadLocal.get())) {
            httpBody = decryptBody(inputMessage);
        } else {
            httpBody = StreamUtils.copyToString(inputMessage.getBody(), Charset.defaultCharset());
        }
        //返回处理后的消息体给messageConvert
        return new SecretHttpMessage(new ByteArrayInputStream(httpBody.getBytes()), inputMessage.getHeaders());
    }

    /**
     * 解密消息体
     *
     * @param inputMessage 消息体
     * @return 明文
     */
    private String decryptBody(HttpInputMessage inputMessage) throws IOException {
        InputStream encryptStream = inputMessage.getBody();
        String requestBody = StreamUtils.copyToString(encryptStream, Charset.defaultCharset());
        // 验签过程
        HttpHeaders headers = inputMessage.getHeaders();
        if (CollectionUtils.isEmpty(headers.get("clientType"))
                || CollectionUtils.isEmpty(headers.get("timestamp"))
                || CollectionUtils.isEmpty(headers.get("salt"))
                || CollectionUtils.isEmpty(headers.get("signature"))) {
            throw new ResultException(SECRET_API_ERROR, "请求解密参数错误，clientType、timestamp、salt、signature等参数传递是否正确传递");
        }

        String timestamp = String.valueOf(Objects.requireNonNull(headers.get("timestamp")).get(0));
        String salt = String.valueOf(Objects.requireNonNull(headers.get("salt")).get(0));
        String signature = String.valueOf(Objects.requireNonNull(headers.get("signature")).get(0));
        String privateKey = SecretFilter.clientPrivateKeyThreadLocal.get();
        ReqSecret reqSecret = JSON.parseObject(requestBody, ReqSecret.class);
        String data = reqSecret.getData();
        String newSignature = "";
        if (!StringUtils.isEmpty(privateKey)) {
            newSignature = Md5Utils.genSignature(timestamp + salt + data + privateKey);
        }
        if (!newSignature.equals(signature)) {
            // 验签失败
            throw new ResultException(SECRET_API_ERROR, "验签失败，请确认加密方式是否正确");
        }

        try {
            String decrypt = EncryptUtils.aesDecrypt(data, privateKey);
            if (StringUtils.isEmpty(decrypt)) {
                decrypt = "{}";
            }
            return decrypt;
        } catch (Exception e) {
            log.error("error: ", e);
        }
        throw new ResultException(SECRET_API_ERROR, "解密失败");
    }
}

SecretResponseAdvice响应加密

@ControllerAdvice
public class SecretResponseAdvice implements ResponseBodyAdvice {
    private Logger logger = LoggerFactory.getLogger(SecretResponseAdvice.class);
    @Autowired
    private ObjectMapper objectMapper;
    @Override
    public boolean supports(MethodParameter methodParameter, Class aClass) {
        return true;
    }

    @Override
    public Object beforeBodyWrite(Object o, MethodParameter methodParameter, MediaType mediaType, Class aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {
        // 判断是否需要加密
        Boolean respSecret = SecretFilter.secretThreadLocal.get();
        String secretKey = SecretFilter.clientPrivateKeyThreadLocal.get();
        // 清理本地缓存
        SecretFilter.secretThreadLocal.remove();
        SecretFilter.clientPrivateKeyThreadLocal.remove();
        if (null != respSecret && respSecret) {
            if (o instanceof ResponseBasic) {
                // 外层加密级异常
                if (SECRET_API_ERROR == ((ResponseBasic) o).getCode()) {
                    return SecretResponseBasic.fail(((ResponseBasic) o).getCode(), ((ResponseBasic) o).getData(), ((ResponseBasic) o).getMsg());
                }
                // 业务逻辑
                try {
                    // 此处使用Jackson加密数据,fastjson加密会导致数据解密后于元数据不一致
                    String dataStr =objectMapper.writeValueAsString(o);
        			String data = EncryptUtils.aesEncrypt(dataStr, secretKey);
                    // 增加签名
                    long timestamp = System.currentTimeMillis() / 1000;
                    int salt = EncryptUtils.genSalt();
                    String dataNew = timestamp + "" + salt + "" + data + secretKey;
                    String newSignature = Md5Utils.genSignature(dataNew);
                    return SecretResponseBasic.success(data, timestamp, salt, newSignature);
                } catch (Exception e) {
                    logger.error("beforeBodyWrite error:", e);
                    return SecretResponseBasic.fail(SECRET_API_ERROR, "", "服务端处理结果数据异常");
                }
            }
        }
        return o;
    }
}