C++

Add a Detached Signature (Header Placement Control)

Demonstrates the Chilkat Mime.AddDetachedSignature2 method, which creates the same multipart/signed structure as AddDetachedSignature, with a second argument controlling whether the existing message header fields are transferred to the new outer entity.

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: Signing wraps the content in a new outer multipart/signed, which raises the question of where the message-level headers (Subject, From, To) should live. This variant lets you choose: transfer them up to the outer entity so the signed message looks like a normal email, or leave them on the inner part. Transferring is typical for email; the finer control matters when the signed entity is embedded in a larger structure.

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C++

#include <CkMime.h>
#include <CkCert.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 signing certificate (which must have access to its private key) from a PFX file.
    //  The PFX password should come from a secure source rather than being hard-coded.
    const char *pfxPassword = "myPfxPassword";
    CkCert cert;
    success = cert.LoadPfxFile("qa_data/signer.pfx",pfxPassword);
    if (success == false) {
        std::cout << cert.lastErrorText() << "\r\n";
        return;
    }

    //  AddDetachedSignature2 is the same as AddDetachedSignature, but the 2nd argument controls whether
    //  the existing message header fields are transferred to the new outer multipart/signed entity.
    bool transferHeaderFields = true;
    success = mime.AddDetachedSignature2(cert,transferHeaderFields);
    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 (headers transferred)." << "\r\n";
    }