System.Security.Cryptography.X509Certificates.X509Certificate.GetCertHashString C# (CSharp) Method

        public virtual string GetCertHashString()
        {
            ThrowIfInvalid();
            return GetRawCertHash().ToHexStringUpper();
        }

        static bool RemoteCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
        {
            if (sslPolicyErrors == SslPolicyErrors.None)
                return true;

            WebRequest request = sender as WebRequest;
            if (request == null || certificate == null)
                return false;

            bool isAllowed;
            string allowed, urn = String.Format("{0}:{1}", request.RequestUri.Host, request.RequestUri.Port);
            if (Storage.Read(urn, certificate.GetCertHashString(), out allowed) && bool.TryParse(allowed, out isAllowed))
                return isAllowed;

            string sslErrorDesc = String.Empty;
            if ((sslPolicyErrors & SslPolicyErrors.RemoteCertificateChainErrors) == SslPolicyErrors.RemoteCertificateChainErrors)
                sslErrorDesc += Resources.RemoteCertificateChainErrors;
            else if ((sslPolicyErrors & SslPolicyErrors.RemoteCertificateNameMismatch) == SslPolicyErrors.RemoteCertificateNameMismatch)
                sslErrorDesc += Resources.RemoteCertificateNameMismatch;
            else if ((sslPolicyErrors & SslPolicyErrors.RemoteCertificateNotAvailable) == SslPolicyErrors.RemoteCertificateNotAvailable)
                sslErrorDesc += Resources.RemoteCertificateNotAvailable;

            sslErrorDesc = String.Format(Resources.SslErrorDescPromptFormat,
                urn, sslErrorDesc, certificate.Subject, certificate.GetCertHashString());

            DialogResult dr = MessageBox.Show(sslErrorDesc, "SSL Error", MessageBoxButtons.YesNo, MessageBoxIcon.Error, MessageBoxDefaultButton.Button2);
            if (dr != DialogResult.Yes)
                return false;

            Storage.Write(urn, certificate.GetCertHashString(), true.ToString());
            return true;
        }