(C++) Send Encrypted Email with a Selected Algorithm (AES, 3DES, etc.)

Sends an encrypted email using the recipient's digital certificate from a .cer file, and chooses 3DES for the encryption algorithm. (It is also possible to send AES encrypted email w/ 128-bit, 192-bit, or 256-bit encryption simply by setting the Pkcs7CryptAlg and Pkcs7KeyLength properties.)

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#include <CkMailMan.h>
#include <CkCert.h>
#include <CkEmail.h>

void ChilkatSample(void)
    {
    // 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.
    CkMailMan mailman;

    // Set the SMTP server.
    mailman.put_SmtpHost("smtp.mymailserver.com");

    // Load the .cer file into a certificate object.
    // When sending S/MIME encrypted email, it is the recipient's
    // certificate that is used for encryption.  Only the public key
    // is needed to encrypt.  The recipient is the only
    // one possessing the private key, and therefore is the only
    // one able to decrypt.
    CkCert cert;
    bool success = cert.LoadFromFile("cknotes.cer");
    if (success != true) {
        std::cout << cert.lastErrorText() << "\r\n";
        return;
    }

    // Create a new email object
    CkEmail email;

    email.put_Subject("This email is encrypted");
    email.put_Body("This is a digitally encrypted mail");
    email.put_From("Chilkat Support <support@chilkatsoft.com>");
    success = email.AddTo("Chilkat Blog","admin@cknotes.com");

    // Indicate that the email is to be sent encrypted.
    email.put_SendEncrypted(true);

    // Specify the certificate to be used for encryption.
    success = email.SetEncryptCert(cert);

    // If desired, specify the encryption algorithm to be used.
    // The Pkcs7CryptAlg property can be set to "aes", "des", "3des", or "rc2"
    email.put_Pkcs7CryptAlg("3des");

    // If desired, set the key length (in bits) for the encryption algorithm:
    // The possible values allowed depend on the Pkcs7CryptAlg property. 
    // For "aes", the key length may be 128, 192, or 256. 
    // For "3des" the key length must be 192. 
    // For "des" the key length must be 40. 
    // For "rc2" the key length can be 40, 56, 64, or 128.
    email.put_Pkcs7KeyLength(192);

    success = mailman.SendEmail(email);
    if (success != true) {
        std::cout << mailman.lastErrorText() << "\r\n";
    }
    else {
        std::cout << "Mail Sent!" << "\r\n";
    }
    }