.Net单点登录详解 (SSO)

最近做GXP(高校平台)的项目，因为里边有好多个子系统，例如有考试系统，评教系统，基础系统，新生入学系统，权限系统，如果每个系统都有自己的独立的登录的界面，那么就会有能访问这五个系统的人就要记住五套用户名，密码。哇，好累啊，五套！在这个背景下提出了单点登录（SSO）。

先来说说什么是单点登录(SSO)，单点登录（Single Sign On），简称为 SSO，是目前比较流行的企业业务整合的解决方案之一。SSO的定义是在多个应用系统中，用户只需要登录一次就可以访问所有相互信任的应用系统。单点登录简单来说，就一处登录，可以到处访问。

SSO的解决方案很多，比如收费的有UTrust、惠普灵动等，开源的有CAS、Smart SSO等，其中应用最为广泛的是CAS。但是因本人能力有限，没有做出cas在.net下的应用。所有这篇文章来介绍一下模拟cas形式做的一个登录，请大家多多批评指正。

让我们来看看cas的工作原理！

当用户在地址栏中输入我们想访问的地址后，例如输入基础系统的url地址，基础系统的服务器会检测有没有发过来票据（ST），如果没有，那么会跳转到认证中心服务器端，当发送到认证中心服务器端后，认证中心服务器端会检查有没有有没有发过来CooKie，如果没有，那么就会那么就会出现登录界面，让用户输入用户名，密码，然后回去数据库中进行验证，如果用户输入的正确，那么会生成一个票据(ST)和保存用户名的Cookie，票据（ST）中包括：要访问系统的URL，和进入该系统的唯一凭证。返回给浏览器，浏览器接受后，会保存Cookie，然后通过ST中的URL转到要访问系统的服务器，进入该服务器后，依然后检测有没有ST,现在又ST，那么他会拿着这个ST中的唯一凭证去认证中心服务器进行比对，看看该唯一凭证是不是认证中心服务器端生成的，如果是的话啊，那么就返回用户信息！并展示页面给用户！。vcD4KPHA+ICAgICAgICAgy7XBy9Xiw7S24KOsuPi087zSv7TSu7j2wP3X06Gjz8i/tNK7z8LV4rj2wP3X07XEveG5uaOhPC9wPgo8cD4gICAgICAgIDxpbWcgc3JjPQ=="/uploadfile/Collfiles/20141129/20141129083547208.jpg" alt="\">

这个例子中有三个项目，分别为：MasterSite，site1，site2.MasterSite 模拟认证中心服务器，site1模拟其中的一个应用，site2模拟另一个应用!

让我们看一下主要的代码！

验证服务器端的登录页的后台代码。首先检查发过来的请求中包含的信息都有什么，

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;

public partial class _Default : System.Web.UI.Page 
{
    /// 
    /// 服务器端的登录页面的类
    /// 
    /// 
    /// 
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            SSORequest ssoRequest = new SSORequest();


            #region 验证 Post 过来的参数
            //--------------------------------
            // 请求注销
            if (!string.IsNullOrEmpty(Request["Logout"]))
            {
                Authentication.Logout();
                return;
            }
            //--------------------------------
            // 各独立站点标识
            if (string.IsNullOrEmpty(Request["IASID"]))
            {
                return;
            }
            else
            {
                ssoRequest.IASID = Request["IASID"];
            }

            //--------------------------------
            // 时间戳
            if (string.IsNullOrEmpty(Request["TimeStamp"]))
            {
                return;
            }
            else
            {
                ssoRequest.TimeStamp = Request["TimeStamp"];
            }

            //--------------------------------
            // 各独立站点的访问地址
            if (string.IsNullOrEmpty(Request["AppUrl"]))
            {
                return;
            }
            else
            {
                ssoRequest.AppUrl = Request["AppUrl"];
            }

            //--------------------------------
            // 各独立站点的 Token
            if (string.IsNullOrEmpty(Request["Authenticator"]))
            {
                return;
            }
            else
            {
                ssoRequest.Authenticator = Request["Authenticator"];
            }

            ViewState["SSORequest"] = ssoRequest;

            #endregion


            //验证从分站发过来的Token
            if (Authentication.ValidateAppToken(ssoRequest))
            {
                string userAccount = null;

                // 验证用户之前是否登录过
                //验证 EAC 认证中心的 Cookie,验证通过时获取用户登录账号
                if (Authentication.ValidateEACCookie(out userAccount))
                {
                    ssoRequest.UserAccount = userAccount;

                    //创建认证中心发往各分站的 Token
                    if (Authentication.CreateEACToken(ssoRequest))
                    {
                        Post(ssoRequest);
                    }
                }
                else
                {
                    return;
                }
            }
            else
            {
                return;
            }
        }
    }


    //post请求
    void Post(SSORequest ssoRequest)
    {
        PostService ps = new PostService();

        ps.Url = ssoRequest.AppUrl;

        ps.Add("UserAccount", ssoRequest.UserAccount);
        ps.Add("IASID", ssoRequest.IASID);
        ps.Add("TimeStamp", ssoRequest.TimeStamp);
        ps.Add("AppUrl", ssoRequest.AppUrl);
        ps.Add("Authenticator", ssoRequest.Authenticator);

        ps.Post();
    }

    /// 
    /// 验证登录账号和密码是否正确
    /// 
    /// 登录账号
    /// 登录密码
    /// 
    private bool ValidateUserInfo(string userName, string userPwd)
    {
        //从数据库中读取,验证登录账号和密码
        //略...
        return true;
    }

    protected void Login1_Authenticate(object sender, AuthenticateEventArgs e)
    {
        if (string.IsNullOrEmpty(Login1.UserName) || string.IsNullOrEmpty(Login1.Password))
        {
            Page.RegisterClientScriptBlock("Add", "<script lanuage=\"javascript\">alert('用户名密码不能为空！');</script>");
            return;
        }
        else if (ValidateUserInfo(Login1.UserName, Login1.Password) == false)
        {
            Page.RegisterClientScriptBlock("Add", "<script lanuage=\"javascript\">alert('用户名密码错误！');</script>");
            return;
        }
        else
        {
            //保存当前用户的用户名
            Session["CurrUserName"] = Login1.UserName;
            //设置过期时间  单位为分钟
            Session.Timeout = 120;

            SSORequest ssoRequest = ViewState["SSORequest"] as SSORequest;

            // 如果不是从各分站 Post 过来的请求，则默认登录主站
            if (ssoRequest == null)
            {
                FormsAuthentication.SetAuthCookie(Login1.UserName, false);

                ssoRequest = new SSORequest();
                //主站标识ID
                ssoRequest.IASID = "00";
                ssoRequest.AppUrl = "SiteList.aspx";
                ssoRequest.TimeStamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm");
                ssoRequest.Authenticator = string.Empty;

                Response.Redirect("SiteList.aspx");
            }
            ssoRequest.UserAccount = Login1.UserName;

            //创建Token
            if (Authentication.CreateEACToken(ssoRequest))
            {
                string expireTime = DateTime.Now.AddHours(3).ToString("yyyy-MM-dd HH:mm");

                Authentication.CreatEACCookie(ssoRequest.UserAccount, ssoRequest.TimeStamp, expireTime);

                Post(ssoRequest);
            }

        }
    }
}

          该类主要是将要发送的请求封装起来成为一个类进行发送！

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

/// 
/// SSORequest  该类主要是设置请求包,请求包中都包括哪些信息!
/// 继承MarshalByRefObject ,主要解决跨域访问的问题!
/// 
[Serializable]
public class SSORequest : MarshalByRefObject
{
    public string IASID;         //各独立站点标识ID
    public string TimeStamp;     //时间戳
    public string AppUrl;        //各独立站点的访问地址
    public string Authenticator; //各独立站点的 Token

    public string UserAccount;   //账号
    public string Password;      //密码

    public string IPAddress;     //IP地址

    //为ssresponse对象做准备
    public string ErrorDescription = "认证失败";   //用户认证通过,认证失败,包数据格式不正确,数据校验不正确
    public int Result = -1;

    public SSORequest()
    {

    }


    /// 
    /// 获取当前页面上的SSORequest对象
    /// 
    /// 
    /// 
    public static SSORequest GetRequest(Page CurrentPage)
    {
        SSORequest request = new SSORequest();
        request.IPAddress = CurrentPage.Request.UserHostAddress;
        request.IASID = CurrentPage.Request["IASID"].ToString();// Request本身会Decode
        request.UserAccount = CurrentPage.Request["UserAccount"].ToString();//this.Text
        request.Password = CurrentPage.Request["Password"].ToString();
        request.AppUrl = CurrentPage.Request["AppUrl"].ToString();
        request.Authenticator = CurrentPage.Request["Authenticator"].ToString();
        request.TimeStamp = CurrentPage.Request["TimeStamp"].ToString();
        return request;
    }
}

该类的主要作用是发送请求,或者将受到的请求进行处理,发后回送请求信息!

using System;
using System.Collections.Generic;
using System.Text;
using System.Web;

/// 
/// 该类的主要作用是发送请求,
/// 或者将受到的请求进行处理,发后回送请求信息!
/// 
public class PostService
{
    private System.Collections.Specialized.NameValueCollection Inputs = new System.Collections.Specialized.NameValueCollection();
    public string Url = "";
    public string Method = "post";
    public string FormName = "form1";

    /// 
    /// 添加需要提交的名和值
    /// 
    /// 
    /// 
    public void Add(string name, string value)
    {
        Inputs.Add(name, value);
    }

    /// 
    /// 以输出Html方式POST
    /// 
    public void Post()
    {
        System.Web.HttpContext.Current.Response.Clear();

        string html = string.Empty;

        html += ("");
        html += (string.Format("", FormName));
        html += (string.Format("", FormName, Method, Url));
        try
        {
            for (int i = 0; i ", Inputs.Keys[i], Inputs[Inputs.Keys[i]]));
            }
            html += ("");
            html += ("");

            System.Web.HttpContext.Current.Response.Write(html);
            System.Web.HttpContext.Current.Response.End();
        }
        catch (Exception e)
        {
            
        }
    }
}

安全验证类，主要对发送过来的票据进行验证！

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Collections.Generic;
using System.Text;

/// 
/// 安全验证类
/// 
public class Authentication
{
    static readonly string cookieName = "EACToken";
    static readonly string hashSplitter = "|";

    public Authentication()
    {
    }

    public static string GetAppKey(int appID)
    {
        //string cmdText = @"select * from ";
        return string.Empty;
    }

    public static string GetAppKey()
    {
        return "22362E7A9285DD53A0BBC2932F9733C505DC04EDBFE00D70";
    }

    public static string GetAppIV()
    {
        return "1E7FA9231E7FA923";
    }

    /// 
    /// 取得加密服务
    /// 
    /// 
    static CryptoService GetCryptoService()
    {
        string key = GetAppKey();
        string IV = GetAppIV();

        CryptoService cs = new CryptoService(key, IV);
        return cs;
    }

    /// 
    /// 创建各分站发往认证中心的 Token
    /// 
    /// 
    /// 
    public static bool CreateAppToken(SSORequest ssoRequest)
    {
        string OriginalAuthenticator = ssoRequest.IASID + ssoRequest.TimeStamp + ssoRequest.AppUrl;
        string AuthenticatorDigest = CryptoHelper.ComputeHashString(OriginalAuthenticator);
        string sToEncrypt = OriginalAuthenticator + AuthenticatorDigest;
        byte[] bToEncrypt = CryptoHelper.ConvertStringToByteArray(sToEncrypt);

        CryptoService cs = GetCryptoService();

        byte[] encrypted;

        if (cs.Encrypt(bToEncrypt, out encrypted))
        {
            ssoRequest.Authenticator = CryptoHelper.ToBase64String(encrypted);

            return true;
        }
        else
        {
            return false;
        }
    }


    /// 
    /// 验证从各分站发送过来的 Token
    /// 
    /// 
    /// 
    public static bool ValidateAppToken(SSORequest ssoRequest)
    {
        string Authenticator = ssoRequest.Authenticator;

        string OriginalAuthenticator = ssoRequest.IASID + ssoRequest.TimeStamp + ssoRequest.AppUrl;
        string AuthenticatorDigest = CryptoHelper.ComputeHashString(OriginalAuthenticator);
        string sToEncrypt = OriginalAuthenticator + AuthenticatorDigest;
        byte[] bToEncrypt = CryptoHelper.ConvertStringToByteArray(sToEncrypt);

        CryptoService cs = GetCryptoService();
        byte[] encrypted;

        if (cs.Encrypt(bToEncrypt, out encrypted))
        {
            return Authenticator == CryptoHelper.ToBase64String(encrypted);
        }
        else
        {
            return false;
        }
    }


    /// 
    /// 创建认证中心发往各分站的 Token
    /// 
    /// 
    /// 
    public static bool CreateEACToken(SSORequest ssoRequest)
    {
        string OriginalAuthenticator = ssoRequest.UserAccount + ssoRequest.IASID + ssoRequest.TimeStamp + ssoRequest.AppUrl;
        string AuthenticatorDigest = CryptoHelper.ComputeHashString(OriginalAuthenticator);
        string sToEncrypt = OriginalAuthenticator + AuthenticatorDigest;
        byte[] bToEncrypt = CryptoHelper.ConvertStringToByteArray(sToEncrypt);

        CryptoService cs = GetCryptoService();
        byte[] encrypted;

        if (cs.Encrypt(bToEncrypt, out encrypted))
        {
            ssoRequest.Authenticator = CryptoHelper.ToBase64String(encrypted);

            return true;
        }
        else
        {
            return false;
        }
    }


    /// 
    /// 验证从认证中心发送过来的 Token
    /// 
    /// 
    /// 
    public static bool ValidateEACToken(SSORequest ssoRequest)
    {
        string Authenticator = ssoRequest.Authenticator;

        string OriginalAuthenticator = ssoRequest.UserAccount + ssoRequest.IASID + ssoRequest.TimeStamp + ssoRequest.AppUrl;
        string AuthenticatorDigest = CryptoHelper.ComputeHashString(OriginalAuthenticator);
        string sToEncrypt = OriginalAuthenticator + AuthenticatorDigest;
        byte[] bToEncrypt = CryptoHelper.ConvertStringToByteArray(sToEncrypt);

        string EncryCurrentAuthenticator = string.Empty;
        CryptoService cs = GetCryptoService();
        byte[] encrypted;

        if (cs.Encrypt(bToEncrypt, out encrypted))
        {
            EncryCurrentAuthenticator = CryptoHelper.ToBase64String(encrypted);

            return Authenticator == EncryCurrentAuthenticator;
        }
        else
        {
            return false;
        }
    }


    /// 
    /// 创建 EAC 认证中心的 Cookie
    /// 
    /// 
    /// 
    /// 
    /// 
    /// 
    public static bool CreatEACCookie(string userAccount, string timeStamp, string expireTime)
    {
        string plainText = "UserAccount=" + userAccount + ";TimeStamp=" + timeStamp + ";ExpireTime=" + expireTime;
        plainText += hashSplitter + CryptoHelper.ComputeHashString(plainText);

        CryptoService cs = GetCryptoService();
        byte[] encrypted;

        if (cs.Encrypt(CryptoHelper.ConvertStringToByteArray(plainText), out encrypted))
        {
            string cookieValue = CryptoHelper.ToBase64String(encrypted);
            SetCookie(cookieValue);

            return true;
        }
        else
        {
            return false;
        }
    }

    /// 
    /// 验证 EAC 认证中心的 Cookie，验证通过时获取用户登录账号
    /// 
    /// 输出用户登录账号
    /// 
    public static bool ValidateEACCookie(out string userAccount)
    {
        userAccount = string.Empty;
        try
        {

            string cookieValue = GetCookie().Value;
            byte[] toDecrypt = CryptoHelper.FromBase64String(cookieValue);
            CryptoService cs = GetCryptoService();

            string decrypted = string.Empty;
            if (cs.Decrypt(toDecrypt, out decrypted))
            {

                string[] arrTemp = decrypted.Split(Convert.ToChar(hashSplitter));
                string plainText = arrTemp[0];
                string hashedText = arrTemp[1];

                userAccount = plainText.Split(Convert.ToChar(";"))[0].Split(Convert.ToChar("="))[1];

                return hashedText.Replace("\0", string.Empty) == CryptoHelper.ComputeHashString(plainText);

            }
            else
            {
                return false;
            }
        }
        catch (Exception e)
        {
            return false;
        }
    }


    public static void Logout()
    {
        HttpContext.Current.Response.Cookies[cookieName].Expires = DateTime.Parse("1900-1-1");
        HttpContext.Current.Response.Cookies[cookieName].Path = "/";
    }

    private static void SetCookie(string cookieValue)
    {
        HttpContext.Current.Response.Cookies[cookieName].Value = cookieValue;
        HttpContext.Current.Response.Cookies[cookieName].Expires = DateTime.Now.AddHours(24);
        HttpContext.Current.Response.Cookies[cookieName].Path = "/";
    }

    private static HttpCookie GetCookie()
    {
        HttpCookie cookie = HttpContext.Current.Request.Cookies["EACToken"];
        return cookie;
    }
}

上边是主站中主要的类的代码，APP_CODE下边的其他两个类主要是进行数据加密用的，这里不再列出！下边看一下分站的代码，大部分的都和主站的代码一样，也包括一个SSORequest和一个PostServer还有另外三个类，下边看一下主页的后台代码

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;

public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            #region SSO 部分代码
            SSORequest ssoRequest = new SSORequest();

            if (string.IsNullOrEmpty(Request["IASID"]))
            {
                ssoRequest.IASID = "01";
                ssoRequest.TimeStamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm");
                ssoRequest.AppUrl = Request.Url.ToString();
                Authentication.CreateAppToken(ssoRequest);

                Post(ssoRequest);
            }
            else if (!string.IsNullOrEmpty(Request["IASID"])
                && !string.IsNullOrEmpty(Request["TimeStamp"])
                && !string.IsNullOrEmpty(Request["AppUrl"])
                && !string.IsNullOrEmpty(Request["UserAccount"])
                && !string.IsNullOrEmpty(Request["Authenticator"]))
            {
                ssoRequest.IASID = Request["IASID"];
                ssoRequest.TimeStamp = Request["TimeStamp"];
                ssoRequest.AppUrl = Request["AppUrl"];
                ssoRequest.UserAccount = Request["UserAccount"];
                ssoRequest.Authenticator = Request["Authenticator"];

                if (Authentication.ValidateEACToken(ssoRequest))
                {
                    //从数据库中获取UserId
                    Session["CurrUserName"] = Request["UserAccount"];
                    Session.Timeout = 120;
                    FormsAuthentication.SetAuthCookie(Request["UserAccount"], false);
                    Response.Write(string.Format("{0},您好！欢迎来到site1,  >> 访问site2", ssoRequest.UserAccount));
                }
            }

            ViewState["SSORequest"] = ssoRequest;

            #endregion
        }
    }

    void Post(SSORequest ssoRequest)
    {
        PostService ps = new PostService();
        //认证中心(主站)地址
        string EACUrl = "https://192.168.24.89:8085";
        ps.Url = EACUrl;
        //ps.Add("UserAccount", ssoRequest.UserAccount);
        ps.Add("IASID", ssoRequest.IASID);
        ps.Add("TimeStamp", ssoRequest.TimeStamp);
        ps.Add("AppUrl", ssoRequest.AppUrl);
        ps.Add("Authenticator", ssoRequest.Authenticator);

        ps.Post();
    }


    //注销登录
    protected void LinkButton2_Click(object sender, EventArgs e)
    {
        FormsAuthentication.SignOut();

        SSORequest ssoRequest = new SSORequest();

        ssoRequest.IASID = "01";
        ssoRequest.TimeStamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm");
        ssoRequest.AppUrl = Request.Url.ToString();

        Authentication.CreateAppToken(ssoRequest);

        PostService ps = new PostService();

        //认证中心(主站)地址
        string EACUrl = "https://192.168.24.89:8085";
        ps.Url = EACUrl;

        ps.Add("IASID", ssoRequest.IASID);
        ps.Add("TimeStamp", ssoRequest.TimeStamp);
        ps.Add("AppUrl", ssoRequest.AppUrl);
        ps.Add("Authenticator", ssoRequest.Authenticator);

        ps.Add("Logout", "true");

        ps.Post();
    }

    //返回主站
    protected void LinkButton1_Click(object sender, EventArgs e)
    {
        if (Session["CurrUserName"] != null)
        {
            Response.Redirect("https://192.168.24.89:8085/MasterSite/SiteList.aspx");
        }
    }
}

可以看到有一个注销登录，他会清空主站的Cookie和分站的Cookie中的信息！

这里仅写了一些主要的类的代码，可以来这里下载DEMO。

在计算机发展的越来越快的时代，好多事情都要放到计算机中进行处理，那么系统也就会随之增多。所以单点登录也就会变得越来越重要！