SHA1 md = new SHA1CryptoServiceProvider();
        byte[] hash = md.ComputeHash( data );
        TimeStampRequestGenerator reqGen = new TimeStampRequestGenerator();
        // требуем сертификат TSA
        reqGen.SetCertReq( true );
        
        TimeStampRequest request = reqGen.Generate( "1.3.14.3.2", hash );
        byte[] reqData = request.GetEncoded();
        WebRequest webRequest = WebRequest.Create(TSP_RSA_URL);        
        //webRequest.Timeout = 10000;        
        webRequest.Method = "POST";
        webRequest.ContentType = "application/timestamp-query";
        
        webRequest.ContentLength = reqData.Length;
        Stream stream = webRequest.GetRequestStream();
        stream.Write(reqData, 0, reqData.Length);
        stream.Close();

        var responseStream = webRequest.GetResponse();
        var a = responseStream.GetResponseStream();
        byte[] resp = new byte[responseStream.ContentLength];
        a.Read( resp, 0,(int) responseStream.ContentLength );
        TimeStampResponse response = new TimeStampResponse( resp );