static void Main(string[] args)
      {
         // To idendify the Smart Card CryptoGraphic Providers on your
         // computer, use the Microsoft Registry Editor (Regedit.exe).
         // The available Smart Card CryptoGraphic Providers are listed
         // in HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography\Defaults\Provider.
 
         // Create a new CspParameters object that identifies a 
         // Smart Card CryptoGraphic Provider.
         // The 1st parameter comes from HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography\Defaults\Provider Types.
         // The 2nd parameter comes from HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography\Defaults\Provider.
 
         CspParameters csp = new CspParameters(1, "eToken Base Cryptographic Provider");
 
         csp.Flags = CspProviderFlags.UseDefaultKeyContainer;
 
         // Initialize an RSACryptoServiceProvider object using
         // the CspParameters object.
 
         RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(csp);
 
         // Create some data to sign.
         byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6, 7 };     // CNPJs vinculados
 
         Console.WriteLine("Data     : " + BitConverter.ToString(data));
 
         // Sign the data using the Smart Card CryptoGraphic Provider.
         byte[] sig = rsa.SignData(data, "SHA256");
 
         Console.WriteLine("Signature: " + BitConverter.ToString(sig));
 
         string base64sign = Convert.ToBase64String(sig);
 
         Console.WriteLine("Base64   : " + base64sign);
         Console.WriteLine("Tamanho  : " + base64sign.Length.ToString());
 
         // Verify the data using the Smart Card CryptoGraphic Provider.
         bool verified = rsa.VerifyData(data, "SHA256", sig);
 
         Console.WriteLine("Verified : " + verified);
      }