Swift

Specify a Certificate for Encrypted Email

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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Swift


func chilkatTest() {
    var success: Bool = 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.

    let email = CkoEmail()!
    email.subject = "Encrypted email"
    email.body = "Encrypted to the specified recipient certificate(s)."
    email.from = "alice@example.com"
    email.add(to: "Bob", emailAddress: "bob@example.com")

    //  Load a recipient certificate (public key) and add it to the encryption cert list.
    let cert = CkoCert()!
    success = cert.load(fromFile: "qa_data/certs/recipient.cer")
    if success == false {
        print("\(cert.lastErrorText!)")
        return
    }

    success = email.addEncryptCert(cert: cert)
    if success == false {
        print("\(email.lastErrorText!)")
        return
    }

    //  Request encrypted sending.
    email.sendEncrypted = true

    print("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.

}