WebApi与手机客户端通信安全机制

最近公司有几个项目需要开发手机客户端，服务器端选用WebApi，那么如何保证手机客户端在请求服务器端时数据不被篡改，如何保证一个http请求的失效机制，下面总结一下我们在项目中针对这两个问题的解决方案。

基本思路如下：

　　用户在成功登陆app客户端之后，手机客户端向服务器端发出的所有的http请求在请求头(HttpHeader)上都会带上下面三个参数：1、Uid(用户ID)，2、Ts（时间戳），3、Sign（签名）。其中Ts是当前时间减去1970-1-1得到的10位的时间时间戳数字，Sign是接口中所有http请求参数与Uid、Ts经过MD5加密后得到的一个字符串。

具体实现如下(客户端的实现，手机客户端生成下面两个参数的思路是一样的)：

1、Ts时间戳

Ts参数可以保证请求的时效性，在手机客户端生成的Ts，在服务器端验证一下，保证请求是在我们规定的时间段内，具体代码如下：

(1)、生成Ts(C#)代码如下，Andriod和IOS可以同理生成

 /// <summary>
        /// 获取十位的时间戳
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public string GenerateTimeStamp(DateTime dt)
        {
            // Default implementation of UNIX time of the current UTC time  
            TimeSpan ts = dt.ToUniversalTime() - new DateTime(1970, 1, 1, 0, 0, 0, 0);
            return Convert.ToInt64(ts.TotalSeconds).ToString();
        }  

(2)、服务器端端验证Ts代码如下，我们规定从手机客户端发到服务器端的请求有效期为5分钟，时间戳参数是跟在Http请求头中

//获取请求头信息
            var requestHeader = HttpContext.Current.Request.Headers;
           
            //10位时间戳
            var Ts = requestHeader.Get("Ts");
            //验证Ts是否合法(请求时间有效时间为：加减5分钟)
            var ts = Ts;//10位时间戳
            if (ts.Length != 10)
            {
                var resp = Request.CreateResponse<string>(HttpStatusCode.OK, "请求已过期", "application/json"); ;

                throw new HttpResponseException(resp);
            }
            var tsDate = ComHelper.ConvertIntDateTime(ts.ToString());
            if (tsDate > DateTime.Now.AddMinutes(5) || tsDate < DateTime.Now.AddMinutes(-5))
            {
                var resp = Request.CreateResponse<string>(HttpStatusCode.OK, "请求已过期", "application/json"); ;

                throw new HttpResponseException(resp);
            }

(3)、ComHelper公共类代码如下

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.Security;

namespace OpenAPITest.App_Start
{
    public class ComHelper
    {
        /// <summary>
        /// 获取post/get集合
        /// </summary>
        /// <param name="ignoreCase">true 不区分大小写，统一返回小写  false 区分大小写</param>
        /// <returns></returns>
        public static SortedDictionary<string, string> GetRequestSortDic(bool ignoreCase)
        {
            int i = 0;
            SortedDictionary<string, string> sArray = new SortedDictionary<string, string>();
            NameValueCollection coll;
            //Load Form variables into NameValueCollection variable.
            coll = HttpContext.Current.Request.Form;

            //coll = HttpContext.Current.Request.Params;

            // Get names of all forms into a string array.
            String[] requestItem = coll.AllKeys;
            for (i = 0; i < requestItem.Length; i++)
            {
                if (ignoreCase)
                    sArray.Add(requestItem[i].ToLower(), GetString(requestItem[i]));
                else
                    sArray.Add(requestItem[i], GetString(requestItem[i]));
            }

            coll = HttpContext.Current.Request.QueryString;
            requestItem = coll.AllKeys;
            for (i = 0; i < requestItem.Length; i++)
            {
                if (ignoreCase)
                    sArray.Add(requestItem[i].ToLower(), GetString(requestItem[i]));
                else
                    sArray.Add(requestItem[i], GetString(requestItem[i]));
            }

            return sArray;
        }
        /// <summary>
        /// 从当前环境中获取
        /// </summary>
        /// <param name="name"></param>
        /// <param name="defValue"></param>
        /// <returns></returns>
        public static string GetString(string name)
        {
            string res = "";
            var v = HttpContext.Current.Request[name];
            if (v != null)
            {
                res = v.ToString();
            }
            return res;
        }

        /// <summary>
        /// 时间戳转为C#格式时间
        /// </summary>
        /// <param name="timeStamp"></param>
        /// <returns></returns>
        public static DateTime ConvertIntDateTime(string timeStamp)
        {
            DateTime dtStart = TimeZone.CurrentTimeZone.ToLocalTime(new DateTime(1970, 1, 1));
            long lTime = long.Parse(timeStamp + "0000000");
            TimeSpan toNow = new TimeSpan(lTime); return dtStart.Add(toNow);
        }
        /// <summary>
        /// MD5加密
        /// </summary>
        /// <param name="str">原串</param>
        /// <param name="code">加密位</param>
        /// <returns></returns>
        public static string ToMD5(string str)
        {
            return FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower();
        }

        /// <summary>
        /// 获取Sign
        /// </summary>
        /// <param name="inputPara"></param>
        /// <param name="privateKey"></param>
        /// <returns></returns>
        public static string GetResponseMysign(SortedDictionary<string, string> inputPara, string privateKey)
        {
            string fullstring = GetPostStrings(inputPara, "_sign") + privateKey;
            return ToMD5(fullstring);
        }
        private static string GetPostStrings(SortedDictionary<string, string> inputPara, string excepted)
        {
            Dictionary<string, string> sPara = new Dictionary<string, string>();

            //过滤空值、sign与sign_type参数
            foreach (KeyValuePair<string, string> temp in inputPara)
            {
                if (temp.Key.ToLower() != excepted && temp.Value != "" && temp.Value != null)
                {
                    sPara.Add(temp.Key.ToLower(), temp.Value);
                }
            }

            //获得签名结果
            StringBuilder prestr = new StringBuilder();
            foreach (KeyValuePair<string, string> temp in sPara)
            {
                prestr.Append(temp.Key + "=" + temp.Value + "&");
            }

            //去掉最後一個&字符
            int nLen = prestr.Length;
            if (nLen > 1)
                prestr.Remove(nLen - 1, 1);
            return prestr.ToString();
        }

        /// <summary>
        /// 获取十位的时间戳
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static string GenerateTimeStamp(DateTime dt)
        {
            // Default implementation of UNIX time of the current UTC time  
            TimeSpan ts = dt.ToUniversalTime() - new DateTime(1970, 1, 1, 0, 0, 0, 0);
            return Convert.ToInt64(ts.TotalSeconds).ToString();
        }  

    }
}

2、Sign签名

(1)、sign的生成规则：服务器端接口中的所有参数+Uid+Ts，去除掉参数中值为空的参数后， 按照参数key值排序，用&链接，并全部转化为小写，然后用MD5加密，通过HttpHeader发送到服务器端接口。

生成Sign大代码如下(C#),Android和IOS可以同理生成

假如手机客户端请求的一个API接口为：http://weapi.com/order/getlist?StatusID=1&CarID=2&CityID=3&name=&key=222

sign=md5(carid=2&cityid=3&key=222&statusid=1&ts=0123456789&uid=110)

(2)、验证客户端的Sign，防止参数被修改

 //请求签名，客户端生成的签名
            var Sign = requestHeader.Get("Sign");
//排序字典，按照key排序
            SortedDictionary<string, string> postValue = null;
            //获取请求中所有的参数
            postValue = ComHelper.GetRequestSortDic(true);
            postValue.Add("Uid", Uid);//API账户名称
            postValue.Add("Ts", Ts);//10位时间戳 

            string APIPrivateKey = "2D7E7C96-DAC5-4526-96C3-C60CDEC4B120";//客户端和手机端保持一致
            //服务器端生成的Sign
            string mysign = ComHelper.GetResponseMysign(postValue, APIPrivateKey);
            if (!Sign.Equals(mysign, StringComparison.InvariantCultureIgnoreCase))
            {
                var resp = Request.CreateResponse<string>(HttpStatusCode.OK, "签名错误", "application/json"); ;

                throw new HttpResponseException(resp);
            }

 3、模拟测试

 (1)C#模拟Http请求，代码如下

 //请求的API地址
            string url = "http://localhost:51942/api/Values/Get?StatusID=1&CarID=2&CityID=3&name=&key=1233";
            //生成Ts
            string Ts = ComHelper.GenerateTimeStamp(DateTime.Now);
            //SortedDictionary会自动按照key值排序
            SortedDictionary<string, string> sortDic = new SortedDictionary<string, string>();
            sortDic.Add("StatusID", "1");
            sortDic.Add("CarID", "2");
            sortDic.Add("CityID", "3");
            sortDic.Add("name", "");
            sortDic.Add("key", "1233");
            sortDic.Add("Uid","110");
            sortDic.Add("Ts", Ts);
            string APIPrivateKey = "2D7E7C96-DAC5-4526-96C3-C60CDEC4B120";//客户端和手机端保持一致,md5加密多使用了一个参数
            //获取Sign签名
            string Sign = ComHelper.GetResponseMysign(sortDic, APIPrivateKey);
            
            //发送请求
            System.Net.WebRequest wReq = System.Net.WebRequest.Create(url);
            wReq.Headers.Add("Uid", "110");
            wReq.Headers.Add("Ts", Ts);
            wReq.Headers.Add("Sign", Sign);

            System.Net.WebResponse wResp = wReq.GetResponse();
            System.IO.Stream respStream = wResp.GetResponseStream();

            using (System.IO.StreamReader reader = new System.IO.StreamReader(respStream, Encoding.UTF8))
            {
                string res= reader.ReadToEnd();
            }

(2)服务器端验证参数，参数验证写在BaseApiController.cs文件中，只要继承该类的都可以验证客户端传过来的参数

 public class ValuesController : BaseApiController
    {
        
        // GET api/values
        public IEnumerable<string> Get(string StatusID,string CarID,string CityID,string name, string key)
        {
            return new string[] { "value1", "value2" };
        }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Http;
using System.Web.Http.Controllers;
using System.Net.Http;
using System.Net;
namespace OpenAPITest.App_Start
{
    public class BaseApiController : ApiController
    {
        /// <summary>
        /// 初始化方法
        /// </summary>
        /// <param name="controllerContext"></param>
        protected override void Initialize(HttpControllerContext controllerContext)
        {
            base.Initialize(controllerContext);
            //获取请求头信息
            var requestHeader = HttpContext.Current.Request.Headers;
            //登录用户的ID
            var Uid = requestHeader.Get("Uid");
            //请求签名
            var Sign = requestHeader.Get("Sign");
            //10位时间戳
            var Ts = requestHeader.Get("Ts");

            //验证请求头信息是否合法
            string errorMsg = CheckRequestHeader(Sign, Ts, Uid);
            //抛出错误信息
            if (!string.IsNullOrWhiteSpace(errorMsg))
            {
                var resp = Request.CreateResponse<string>(HttpStatusCode.OK, "认证失败", "application/json"); ;
                throw new HttpResponseException(resp);
            }
            //验证Ts是否合法(请求时间有效时间为：加减5分钟)
            var ts = Ts;//10位时间戳
            if (ts.Length != 10)
            {
                var resp = Request.CreateResponse<string>(HttpStatusCode.OK, "请求已过期", "application/json"); ;

                throw new HttpResponseException(resp);
            }
            var tsDate = ComHelper.ConvertIntDateTime(ts.ToString());
            if (tsDate > DateTime.Now.AddMinutes(5) || tsDate < DateTime.Now.AddMinutes(-5))
            {
                var resp = Request.CreateResponse<string>(HttpStatusCode.OK, "请求已过期", "application/json"); ;

                throw new HttpResponseException(resp);
            }

            //排序字典，按照key排序
            SortedDictionary<string, string> postValue = null;
            //获取请求中所有的参数
            postValue = ComHelper.GetRequestSortDic(true);
            postValue.Add("Uid", Uid);//API账户名称
            postValue.Add("Ts", Ts);//10位时间戳 

            string APIPrivateKey = "2D7E7C96-DAC5-4526-96C3-C60CDEC4B120";//客户端和手机端保持一致
            //服务器端生成的Sign
            string mysign = ComHelper.GetResponseMysign(postValue, APIPrivateKey);
            if (!Sign.Equals(mysign, StringComparison.InvariantCultureIgnoreCase))
            {
                var resp = Request.CreateResponse<string>(HttpStatusCode.OK, "签名错误", "application/json"); ;

                throw new HttpResponseException(resp);
            }
            //验证通过


        }

        /// <summary>
        /// 验证请求头
        /// </summary>
        /// <param name="Sign"></param>
        /// <param name="Ts"></param>
        /// <param name="Pid"></param>
        /// <returns></returns>
        private string CheckRequestHeader(string Sign, string Ts, string Uid)
        {
            string ErrorMsg = "";
            //请求签名
            if (string.IsNullOrWhiteSpace(Sign))
            {
                ErrorMsg = "认证失败";
            }
            //10位时间戳 
            else if (string.IsNullOrWhiteSpace(Ts))
            {
                ErrorMsg = "认证失败";
            }
            //API账户名称
            else if (string.IsNullOrWhiteSpace(Uid))
            {
                ErrorMsg = "认证失败";
            }
            return ErrorMsg;
        }
    }
}

作者：Eric.Chen
出处：https://www.cnblogs.com/lc-chenlong
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