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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C++

#include <CkMime.h>
#include <CkCert.h>
#include <CkPrivateKey.h>

void ChilkatSample(void)
    {
    bool success = false;

    CkMime mime;
    success = mime.SetBodyFromPlainText("This message will be signed.");
    if (success == false) {
        std::cout << mime.lastErrorText() << "\r\n";
        return;
    }

    //  Load the certificate and its private key separately.
    CkCert cert;
    success = cert.LoadFromFile("qa_data/signer.cer");
    if (success == false) {
        std::cout << cert.lastErrorText() << "\r\n";
        return;
    }

    CkPrivateKey privKey;
    success = privKey.LoadPemFile("qa_data/signer_privkey.pem");
    if (success == false) {
        std::cout << privKey.lastErrorText() << "\r\n";
        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) {
        std::cout << mime.lastErrorText() << "\r\n";
        return;
    }

    success = mime.SaveMime("qa_output/signed.eml");
    if (success == false) {
        std::cout << mime.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Detached signature added." << "\r\n";
    }