(C) POP3 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.

Chilkat C/C++ Library Downloads
MS Visual C/C++ C++ Builder Linux C/C++ Alpine Linux C/C++	MacOS C/C++ iOS C/C++ Android C/C++ MinGW C/C++

#include <C_CkMailMan.h>
#include <C_CkStringTable.h>
#include <C_CkEmail.h>
#include <C_CkCert.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkMailMan mailman;
    HCkStringTable stUidls;
    HCkEmail email;
    HCkCert cert;
    int count;
    int i;

    success = FALSE;

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

    mailman = CkMailMan_Create();

    // Set the POP3 server's hostname
    CkMailMan_putMailHost(mailman,"pop.example.com");

    // Set the POP3 login/password.
    CkMailMan_putPopUsername(mailman,"myLogin");
    CkMailMan_putPopPassword(mailman,"myPassword");

    stUidls = CkStringTable_Create();
    success = CkMailMan_FetchUidls(mailman,stUidls);
    if (success == FALSE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkMailMan_Dispose(mailman);
        CkStringTable_Dispose(stUidls);
        return;
    }

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

    count = CkStringTable_getCount(stUidls);
    i = 0;
    while (i < count) {
        // Download the full email.
        success = CkMailMan_FetchByUidl(mailman,CkStringTable_stringAt(stUidls,i),FALSE,0,email);
        if (success == FALSE) {
            printf("%s\n",CkMailMan_lastErrorText(mailman));
            CkMailMan_Dispose(mailman);
            CkStringTable_Dispose(stUidls);
            CkEmail_Dispose(email);
            CkCert_Dispose(cert);
            return;
        }

        printf("%d\n",i);
        printf("From: %s\n",CkEmail_ck_from(email));
        printf("Subject: %s\n",CkEmail_subject(email));

        // 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));

                success = CkEmail_LastSignerCert(email,0,cert);
                if (success == FALSE) {
                    printf("%s\n",CkEmail_lastErrorText(email));
                    CkMailMan_Dispose(mailman);
                    CkStringTable_Dispose(stUidls);
                    CkEmail_Dispose(email);
                    CkCert_Dispose(cert);
                    return;
                }

                printf("Signing cert: %s\n",CkCert_subjectCN(cert));
            }

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

        i = i + 1;
    }

    CkMailMan_Pop3EndSession(mailman);


    CkMailMan_Dispose(mailman);
    CkStringTable_Dispose(stUidls);
    CkEmail_Dispose(email);
    CkCert_Dispose(cert);

    }