(C# UWP/WinRT) Send Encrypted Email to Multiple Recipients

Demonstrates how to create and send an S/MIME encrypted email to multiple recipients. The digital certificate of each recipient is required. The encrypting/sending process uses each recipient's digital certificate (which internally contains the public key). Each recipient decrypts the received email using his/her private key.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// The mailman object is used for sending and receiving email.
Chilkat.MailMan mailman = new Chilkat.MailMan();

// Set the SMTP server.
mailman.SmtpHost = "smtp.mymailserver.com";

// Load each recipient's certificate into a Chilkat certificate object.
// This example loads the certificates from files.  However, the Chilkat
// certificate object provides other means for loading certificates,
// such as from in-memory PEM strings, or in-memory binary DER encoded form, etc.
Chilkat.Cert cert1 = new Chilkat.Cert();
bool success = cert1.LoadFromFile("recipient1.cer");
if (success != true) {
    Debug.WriteLine(cert1.LastErrorText);
    return;
}

Chilkat.Cert cert2 = new Chilkat.Cert();
success = cert2.LoadFromFile("recipient2.cer");
if (success != true) {
    Debug.WriteLine(cert2.LastErrorText);
    return;
}

Chilkat.Cert cert3 = new Chilkat.Cert();
success = cert3.LoadFromFile("recipient3.cer");
if (success != true) {
    Debug.WriteLine(cert3.LastErrorText);
    return;
}

// Create a new email object
Chilkat.Email email = new Chilkat.Email();

email.Subject = "This email is encrypted and sent to 3 recipients";
email.Body = "This is an S/MIME encrypted mail sent to 3 recipients";
email.From = "Chilkat Support <support@chilkatsoft.com>";

// Make each of the certificates available for encrypting the email
// by calling AddEncryptCert for each.
success = email.AddEncryptCert(cert1);
if (success == true) {
    success = email.AddEncryptCert(cert2);
}

if (success == true) {
    success = email.AddEncryptCert(cert3);
}

if (success != true) {
    Debug.WriteLine(email.LastErrorText);
    return;
}

// Add 3 recipients to the email (2 TO addresses, and 1 CC address)
success = email.AddTo("Recipient 1","admin@cknotes.com");
success = email.AddTo("Recipient 2","somebody001122@yahoo.com");
success = email.AddCC("Recipient 3","somebody123xyz@gmail.com");

// Indicate that the email is to be sent encrypted.
email.SendEncrypted = true;

// Send the encrypted email...
success = await mailman.SendEmailAsync(email);
if (success != true) {
    Debug.WriteLine(mailman.LastErrorText);
}
else {
    Debug.WriteLine("Encrypted Email Sent!");
}