(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 <C_CkImap.h>
#include <C_CkMessageSet.h>
#include <C_CkEmail.h>
#include <C_CkCert.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkImap imap;
    BOOL fetchUids;
    HCkMessageSet messageSet;
    HCkEmail email;
    HCkCert cert;
    int i;
    const char *uid;

    success = FALSE;

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

    imap = CkImap_Create();

    // Connect to an IMAP server.
    // Use TLS
    CkImap_putSsl(imap,TRUE);
    CkImap_putPort(imap,993);
    success = CkImap_Connect(imap,"imap.example.com");
    if (success == FALSE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        return;
    }

    success = CkImap_Login(imap,"myLogin","myPassword");
    if (success == FALSE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        return;
    }

    // Select an IMAP mailbox
    success = CkImap_SelectMailbox(imap,"Inbox");
    if (success == FALSE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        return;
    }

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

    // Get the message IDs of all the emails in the mailbox
    messageSet = CkMessageSet_Create();
    success = CkImap_QueryMbx(imap,"ALL",fetchUids,messageSet);
    if (success == FALSE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        CkMessageSet_Dispose(messageSet);
        return;
    }

    email = CkEmail_Create();
    cert = CkCert_Create();

    i = 0;
    while (i < CkMessageSet_getCount(messageSet)) {

        uid = CkMessageSet_GetId(messageSet,i);
        printf("uid: %s\n",uid);

        success = CkImap_FetchEmail(imap,FALSE,uid,TRUE,email);
        if (success == FALSE) {
            printf("%s\n",CkImap_lastErrorText(imap));
            CkImap_Dispose(imap);
            CkMessageSet_Dispose(messageSet);
            CkEmail_Dispose(email);
            CkCert_Dispose(cert);
            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 (CkEmail_getReceivedSigned(email) == TRUE) {

            printf("This email was signed.\n");

            // Check to see if the signatures were verified.
            if (CkEmail_getSignaturesValid(email) == TRUE) {
                printf("Digital signature(s) verified.\n");
                printf("Signer: %s\n",CkEmail_signedBy(email));

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

                if (success == FALSE) {
                    printf("Failed to get signing certificate object.\n");
                }
                else {
                    printf("Signing cert: %s\n",CkCert_subjectCN(cert));
                }

            }
            else {
                printf("Digital signature verification failed.\n");
            }

        }

        i = i + 1;
    }

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


    CkImap_Dispose(imap);
    CkMessageSet_Dispose(messageSet);
    CkEmail_Dispose(email);
    CkCert_Dispose(cert);

    }