private string Decrypt_CAPICOM(string encryptedData)
        {
            EnvelopedDataClass envelopedData = new EnvelopedDataClass();

            envelopedData.Decrypt(encryptedData);
            return(envelopedData.Content);
        }
        private string Encrypt_CAPICOM(string plainText, Certificate cert)
        {
            EnvelopedDataClass envelopedData = new EnvelopedDataClass();

            envelopedData.Content = plainText;
            envelopedData.Recipients.Add(cert);
            return(envelopedData.Encrypt(CAPICOM_ENCODING_TYPE.CAPICOM_ENCODE_BASE64));
        }