Unicode C++

Add a Detached Signature with a Separate Private Key

Demonstrates the Chilkat Mime.AddDetachedSignaturePk method, which creates a detached signature using a signer certificate and its separately supplied private key. The first argument is the Cert and the second is the PrivateKey.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Sometimes the certificate and its private key live apart — a .cer alongside a PEM key file, for instance — rather than bundled in a single PFX. This method pairs them explicitly for signing, whereas AddDetachedSignature expects a Cert that already provides its key. The result is the same multipart/signed message.

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Unicode C++

#include <CkMimeW.h>
#include <CkCertW.h>
#include <CkPrivateKeyW.h>

void ChilkatSample(void)
    {
    bool success = false;

    CkMimeW mime;
    success = mime.SetBodyFromPlainText(L"This message will be signed.");
    if (success == false) {
        wprintf(L"%s\n",mime.lastErrorText());
        return;
    }

    //  Load the certificate and its private key separately.
    CkCertW cert;
    success = cert.LoadFromFile(L"qa_data/signer.cer");
    if (success == false) {
        wprintf(L"%s\n",cert.lastErrorText());
        return;
    }

    CkPrivateKeyW privKey;
    success = privKey.LoadPemFile(L"qa_data/signer_privkey.pem");
    if (success == false) {
        wprintf(L"%s\n",privKey.lastErrorText());
        return;
    }

    //  Create a detached signature when the certificate and private key are supplied separately.  The
    //  1st argument is the signer certificate and the 2nd is its private key.
    success = mime.AddDetachedSignaturePk(cert,privKey);
    if (success == false) {
        wprintf(L"%s\n",mime.lastErrorText());
        return;
    }

    success = mime.SaveMime(L"qa_output/signed.eml");
    if (success == false) {
        wprintf(L"%s\n",mime.lastErrorText());
        return;
    }

    wprintf(L"Detached signature added.\n");
    }