获取 ssl 证书信息 - .net

Question

我希望从任何给定的域名 SSL 证书中获取数据。例如，我想输入任何网站地址，例如“http://stackoverflow.com”，我的代码将首先检查 SSL 证书是否存在。如果是这样，那么我希望它提取证书的到期日期。 [我正在从数据库中读取域名] 示例：http://www.digicert.com/help/

我需要创建一个网络服务来检查到期日期。我该如何实施？ - 我查看了很多不同的东西，例如 RequestCertificateValidationCallback 和 ClientCertificates 等。由于我是新手，我不确定要做什么。

我可能完全错了（因此我需要帮助），但我会创建一个 HTTPWebRequest，然后以某种方式请求客户端证书和特定元素吗？

我尝试了提供 @SSL 证书预取 .NET 的示例，但我遇到了被禁止的 403 错误。

任何帮助将不胜感激 - 谢谢。

这是我编写的抛出 403 禁止错误的代码。

        Uri u = new Uri("http://services.efi.com/");
        ServicePoint sp = ServicePointManager.FindServicePoint(u);

        string groupName = Guid.NewGuid().ToString();
        HttpWebRequest req = HttpWebRequest.Create(u) as HttpWebRequest;
        req.Accept = "*/*";
        req.ConnectionGroupName = groupName;

        using (WebResponse resp = req.GetResponse())
        {
            // Ignore response, and close the response.
        }
        sp.CloseConnectionGroup(groupName);

        // Implement favourite null check pattern here on sp.Certificate
        string expiryDate = sp.Certificate.GetExpirationDateString();

        string str = expiryDate;

Answer 1

这很好用：

namespace ConsoleApplication1
{
  using System;
  using System.Net;
  using System.Net.Security;
  using System.Security.Cryptography.X509Certificates;

  class Program
  {
    static void Main()
    {
      ServicePointManager.ServerCertificateValidationCallback += ServerCertificateValidationCallback;

      var request = WebRequest.Create("https://www.google.com");

      var response = request.GetResponse();

      Console.WriteLine("Done.");
      Console.ReadLine();

    }

    private static bool ServerCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
    {
      Console.WriteLine("Certificate expires on " + certificate.GetExpirationDateString());

      return true;
    }
  }
}

Answer 2

您将获得“403 禁止”状态，因为这是您访问该页面时服务器返回的状态。当我使用 IE 浏览到该 Uri 时，我看到了同样的事情。此状态表明您无权访问该 Url，因此也许您应该在您有权访问的页面上尝试您的代码。

此外，您不太可能在 http 连接上看到证书 - 您可能想改用 https。

Answer 3

如果需要下载证书：

            //Do webrequest to get info on secure site
        var certName = "FileName";
        var url = "https://mail.google.com";
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        response.Close();

        //retrieve the ssl cert and assign it to an X509Certificate object
        X509Certificate cert = request.ServicePoint.Certificate;

        //convert the X509Certificate to an X509Certificate2 object by passing it into the constructor
        X509Certificate2 cert2 = new X509Certificate2(cert);

        string cn = cert2.GetIssuerName();
        string cedate = cert2.GetExpirationDateString();
        string cpub = cert2.GetPublicKeyString();

        var path = Directory.GetCurrentDirectory() + string.Concat("\\", certName, ".der");
        byte[] certData = cert2.Export(X509ContentType.Cert);
        File.WriteAllBytes(path, certData);

        Console.WriteLine("cert2.GetIssuerName :{0}", cert2.GetIssuerName());
        Console.WriteLine("cert2.GetExpirationDateString :{0}", cert2.GetExpirationDateString());
        Console.WriteLine("cert2.GetPublicKeyString :{0}", cert2.GetPublicKeyString());

.cs 示例文件：https://gist.github.com/thedom85/6db200104c075310527aaef63b172253

我也推荐这个网站：https://www.simple-talk.com/dotnet/.net-framework/tlsssl-and-.net-framework-4.0/