(C++) IMAP Download and Verify Signed (S/MIME) Email

Demonstrates how to download and verify digitally signed S/MIME email.

Note: This example requires Chilkat v11.0.0 or greater.

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#include <CkImap.h>
#include <CkMessageSet.h>
#include <CkEmail.h>
#include <CkCert.h>

void ChilkatSample(void)
    {
    bool success = false;

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

    CkImap imap;

    // Connect to an IMAP server.
    // Use TLS
    imap.put_Ssl(true);
    imap.put_Port(993);
    success = imap.Connect("imap.example.com");
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    success = imap.Login("myLogin","myPassword");
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    // Select an IMAP mailbox
    success = imap.SelectMailbox("Inbox");
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    // We can choose to fetch UIDs or sequence numbers.
    bool fetchUids = true;

    // Get the message IDs of all the emails in the mailbox
    CkMessageSet messageSet;
    success = imap.QueryMbx("ALL",fetchUids,messageSet);
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    CkEmail email;
    CkCert cert;

    int i = 0;
    while (i < messageSet.get_Count()) {

        const char *uid = messageSet.GetId(i);
        std::cout << "uid: " << uid << "\r\n";

        success = imap.FetchEmail(false,uid,true,email);
        if (success == false) {
            std::cout << imap.lastErrorText() << "\r\n";
            return;
        }

        // The security layers of signed and/or encrypted emails
        // are automatically "unwrapped" when loaded into
        // a Chilkat email object.
        // An application only needs to check to see if an email
        // was received signed or encrypted, and then examine
        // the success/failure.  For example:
        if (email.get_ReceivedSigned() == true) {

            std::cout << "This email was signed." << "\r\n";

            // Check to see if the signatures were verified.
            if (email.get_SignaturesValid() == true) {
                std::cout << "Digital signature(s) verified." << "\r\n";
                std::cout << "Signer: " << email.signedBy() << "\r\n";

                // Get the certificate used for signing.
                success = email.LastSignerCert(0,cert);

                if (success == false) {
                    std::cout << "Failed to get signing certificate object." << "\r\n";
                }
                else {
                    std::cout << "Signing cert: " << cert.subjectCN() << "\r\n";
                }

            }
            else {
                std::cout << "Digital signature verification failed." << "\r\n";
            }

        }

        i = i + 1;
    }

    // Disconnect from the IMAP server.
    success = imap.Disconnect();
    }