Unicode C

S/MIME Decrypt using Certificate and Private Key in Apple Keychain

See more Apple Keychain Examples

Decrypts S/MIME using a certificate with private key found in the Apple Keychain. Unicode C

#include <C_CkCertW.h>
#include <C_CkMimeW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkCertW cert;
    HCkMimeW mime;

    success = FALSE;

    cert = CkCertW_Create();

    //  Load the certificate to be used for decryption by the Subject Common Name
    //  On MacOS and iOS, Chilkat will search the Keychain(s) for the matching certificate.
    //  Note: The private key must be present to decrypt.
    success = CkCertW_LoadByCommonName(cert,L"My Cert");
    if (success == FALSE) {
        wprintf(L"%s\n",CkCertW_lastErrorText(cert));
        CkCertW_Dispose(cert);
        return;
    }

    wprintf(L"Cert has private key: %d\n",CkCertW_HasPrivateKey(cert));

    //  Load the MIME to be decrypted.
    //  We encrypted using this example:  S/MIME Encrypt using Certificate in Apple Keychain
    mime = CkMimeW_Create();
    success = CkMimeW_LoadMimeFile(mime,L"./encrypted.mime");
    if (success == FALSE) {
        wprintf(L"%s\n",CkMimeW_lastErrorText(mime));
        CkCertW_Dispose(cert);
        CkMimeW_Dispose(mime);
        return;
    }

    wprintf(L"%s\n",CkMimeW_getMime(mime));
    wprintf(L"----\n");

    //  Here's the encrypted MIME:

    //  Subject: test
    //  SomeHeader: 123
    //  Content-Type: application/x-pkcs7-mime; name="smime.p7m"; smime-type="enveloped-data"
    //  Content-Disposition: attachment; filename="smime.p7m"
    //  Content-Transfer-Encoding: base64
    //  
    //  MIICSwYJKoZIhvcNAQcDoIICPDCCAjgCAQAxggGzMIIBrwIBADCBljCBgTELMAkGA1UEBhMCSVQx
    //  EDAOBgNVBAgMB0JlcmdhbW8xGTAXBgNVBAcMEFBvbnRlIFNhbiBQaWV0cm8xFzAVBgNVBAoMDkFj
    //  dGFsaXMgUy5wLkEuMSwwKgYDVQQDDCNBY3RhbGlzIENsaWVudCBBdXRoZW50aWNhdGlvbiBDQSBH
    //  MwIQPCWvkSv8oQ7xRmEHJ6TzEDANBgkqhkiG9w0BAQEFAASCAQB3VZvHRE5EWxug7Sckpcz1ucDZ
    //  YiTKiqmyPt75MhzNRQLtKFx/jWwlemUwnPMzeu6yutCkZ74Bdn7MBsfDqV3bUz43wAu+fRBteGvF
    //  mTc00MfY8L7o8dkpj4AqAOCj4hKQzbSE99GvSzyXcPE2Gm5NrOPtKxqfFqbBRTCb4fBZP84LaL+x
    //  rnYfrM4qXTppixyN8iFYCd4maEbMu/GA5o+j0BkDDnx42pILDoAGV/ERyx55Y3Nc2Mhm/cITBMNn
    //  g7uS9KPrlYizNaqVu09Hi9jg4gdZaRiTjUqg05tSOk/YqIQxTgfscwSPY92/ewpI6e1EHtLt8Q33
    //  gWCbERptSntUMHwGCSqGSIb3DQEHATAdBglghkgBZQMEAQIEENm1AxeXlEMx7p6McjHIj5CAUEQj
    //  0GuJ5LnTqiqIjOiwmwNidl1N1TRluxX5vAQvwBuYE6bQK4+i04yn2Av3cucW4kvxgP2Nmni+XgQt
    //  aPPKlasaVceEeZ15IYjw77/m3YYn

    //  -------------------------------------
    //  Decrypt the MIME.
    success = CkMimeW_DecryptUsingCert(mime,cert);
    if (success == FALSE) {
        wprintf(L"%s\n",CkMimeW_lastErrorText(mime));
        CkCertW_Dispose(cert);
        CkMimeW_Dispose(mime);
        return;
    }

    //  -------------------------------------
    //  Note: A password dialog may be shown, possibly twice, when accessing the private key.
    //  See the following blog post explaining how to suppress the dialog:
    //  Suppress Password Dialog when Accessing Private Key in Apple Keychain

    //  Show the unencrypted MIME
    wprintf(L"%s\n",CkMimeW_getMime(mime));

    //  Here's the decrypted MIME

    //  Subject: test
    //  SomeHeader: 123
    //  Content-Type: text/plain
    //  
    //  This is the body.


    CkCertW_Dispose(cert);
    CkMimeW_Dispose(mime);

    }