X509Store store = new X509Store("My", StoreLocation.CurrentUser);
            store.Open(OpenFlags.OpenExistingOnly | OpenFlags.ReadOnly);
            X509Certificate2Collection found =
                store.Certificates.Find(X509FindType.FindBySubjectName,
                "Компания ))", false);
            // 
            X509Certificate2 Certificate = found[0];

            AsymmetricAlgorithm Key = Certificate.PrivateKey;

            ASCIIEncoding converter = new ASCIIEncoding();
            byte[] originalData = converter.GetBytes("Подписать эту строку.");
            
            Gost3410CryptoServiceProvider Gost = new Gost3410CryptoServiceProvider();
            Gost3411CryptoServiceProvider GostHash = new Gost3411CryptoServiceProvider();

            byte[] signedData = Gost.SignData(originalData, 0, originalData.Length, GostHash);

            CspParameters cspParameters = new CspParameters() { 
                KeyPassword = GetSecureString("12345") , 
                KeyContainerName = @"\\.\CountDown\Организация", 
                Flags = CspProviderFlags.NoPrompt, ProviderType = 75 };

            Gost3410CryptoServiceProvider Gost = new Gost3410CryptoServiceProvider(cspParameters);