Set Cert and Private Key for S/MIME Decryption

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Demonstrates the Chilkat Imap.SetDecryptCert2 method, which specifies a certificate together with a separately supplied private key for decrypting S/MIME messages. The first argument is the Cert and the second is the PrivateKey. This example loads the certificate and key from separate files.

Note: The certificate path is relative to the application's current working directory. Supply the path to your own certificate file.

Background: Sometimes the certificate (the public part) and the private key are stored separately — a .cer alongside a PEM key file, for instance. This method pairs them explicitly, whereas SetDecryptCert expects a single Cert that already provides its private key. After the pairing, subsequently downloaded S/MIME messages are decrypted automatically.

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#include <C_CkImap.h>
#include <C_CkCert.h>
#include <C_CkPrivateKey.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkImap imap;
    HCkCert cert;
    HCkPrivateKey privKey;

    success = FALSE;

    //  Demonstrates the Imap.SetDecryptCert2 method, which specifies a certificate together with a
    //  separately supplied private key for decrypting S/MIME messages.  The 1st argument is the
    //  Cert and the 2nd is the PrivateKey.

    imap = CkImap_Create();

    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,"user@example.com","myPassword");
    if (success == FALSE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        return;
    }

    //  Load the certificate and its private key from separate files.
    cert = CkCert_Create();
    success = CkCert_LoadFromFile(cert,"qa_data/smime.cer");
    if (success == FALSE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkImap_Dispose(imap);
        CkCert_Dispose(cert);
        return;
    }

    privKey = CkPrivateKey_Create();
    success = CkPrivateKey_LoadPemFile(privKey,"qa_data/smime_privkey.pem");
    if (success == FALSE) {
        printf("%s\n",CkPrivateKey_lastErrorText(privKey));
        CkImap_Dispose(imap);
        CkCert_Dispose(cert);
        CkPrivateKey_Dispose(privKey);
        return;
    }

    //  Use the cert and key to automatically decrypt subsequently downloaded S/MIME messages.
    success = CkImap_SetDecryptCert2(imap,cert,privKey);
    if (success == FALSE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        CkCert_Dispose(cert);
        CkPrivateKey_Dispose(privKey);
        return;
    }

    success = CkImap_Disconnect(imap);
    if (success == FALSE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        CkCert_Dispose(cert);
        CkPrivateKey_Dispose(privKey);
        return;
    }



    CkImap_Dispose(imap);
    CkCert_Dispose(cert);
    CkPrivateKey_Dispose(privKey);

    }