public static X509Certificate2 GetCertificate(StoreName storeName, StoreLocation storeLocation, string certThumbprint)
        {
            X509Store store = new X509Store(storeName, storeLocation);
            store.Open(OpenFlags.OpenExistingOnly | OpenFlags.ReadOnly);
            X509Certificate2Collection certCol = store.Certificates.Find(X509FindType.FindByThumbprint, certThumbprint, false);
            return (certCol.Count == 1) ? certCol[0] : null;
        }