(MFC) IMAP Download and Verify Signed (S/MIME) Email

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

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

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

void ChilkatSample(void)
    {
    CkString strOut;

    // 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);
    bool success = imap.Connect("imap.someMailServer.com");
    if (success != true) {
        strOut.append(imap.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    success = imap.Login("myLogin","myPassword");
    if (success != true) {
        strOut.append(imap.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Select an IMAP mailbox
    success = imap.SelectMailbox("Inbox");
    if (success != true) {
        strOut.append(imap.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        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 = imap.Search("ALL",fetchUids);
    if (imap.get_LastMethodSuccess() != true) {
        strOut.append(imap.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Scan for emails with attachments, and save the attachments
    // to a sub-directory.
    int i = 0;
    while (i < messageSet->get_Count()) {

        const char *uid = messageSet->GetId(i);
        strOut.append("uid: ");
        strOut.append(uid);
        strOut.append("\r\n");

        CkEmail *email = imap.FetchSingle(uid,true);

        // 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) {

            strOut.append("This email was signed.");
            strOut.append("\r\n");

            // Check to see if the signatures were verified.
            if (email->get_SignaturesValid() == true) {
                strOut.append("Digital signature(s) verified.");
                strOut.append("\r\n");

                strOut.append("Signer: ");
                strOut.append(email->signedBy());
                strOut.append("\r\n");

                // The certificate used for signing may be obtained
                // by calling email.GetSignedByCert.
                CkCert *cert = email->GetSignedByCert();
                if (email->get_LastMethodSuccess() != true) {
                    strOut.append("Failed to get signing certificate object.");
                    strOut.append("\r\n");
                }
                else {
                    strOut.append("Signing cert: ");
                    strOut.append(cert->subjectCN());
                    strOut.append("\r\n");
                    delete cert;
                }

            }
            else {
                strOut.append("Digital signature verification failed.");
                strOut.append("\r\n");
            }

        }

        delete email;

        i = i + 1;
    }

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

    delete messageSet;


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }