Specify a Certificate for Encrypted Email

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Demonstrates the Chilkat Email.AddEncryptCert method, which explicitly specifies a certificate to use when sending encrypted email. Call it once per recipient certificate; ClearEncryptCerts clears the list. This example loads a recipient certificate, registers it, and enables encrypted sending.

Background: When encrypting to multiple people, each recipient needs to be able to decrypt with their own private key. S/MIME handles this by encrypting the message's one-time content key separately under each recipient's public certificate and including all of those wrapped keys in the message. AddEncryptCert is how you build that recipient list — one call per certificate — giving explicit control over exactly whose certificates are used rather than relying on automatic lookup.

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bool success = false;

//  Demonstrates the AddEncryptCert method, which explicitly specifies a certificate for
//  sending encrypted email.  Call it once per recipient certificate.  Use ClearEncryptCerts
//  to clear the list.

Chilkat.Email email = new Chilkat.Email();
email.Subject = "Encrypted email";
email.Body = "Encrypted to the specified recipient certificate(s).";
email.From = "alice@example.com";
email.AddTo("Bob","bob@example.com");

//  Load a recipient certificate (public key) and add it to the encryption cert list.
Chilkat.Cert cert = new Chilkat.Cert();
success = cert.LoadFromFile("qa_data/certs/recipient.cer");
if (success == false) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

success = email.AddEncryptCert(cert);
if (success == false) {
    Debug.WriteLine(email.LastErrorText);
    return;
}

//  Request encrypted sending.
email.SendEncrypted = true;

Debug.WriteLine("Added the recipient's encryption certificate.");

//  Note: The path "qa_data/certs/recipient.cer" is a relative local filesystem path,
//  relative to the current working directory of the running application.