MIME S/MIME Signing Algorithm Properties

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Demonstrates the properties that control S/MIME signing: SigningAlg (the RSA signature scheme, PKCS1-V1_5 or RSASSA-PSS), SigningHashAlg (the message-digest algorithm), Micalg and Protocol (the micalg and protocol parameters of a multipart/signed Content-Type), and UseXPkcs7 (whether historical x-pkcs7 media-type names are used). The properties are configured before creating a detached signature.

#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;
    }

    //  SigningAlg is the RSA signature scheme.  The default is PKCS1-V1_5; set RSASSA-PSS (or pss) for
    //  RSASSA-PSS.
    mime.put_SigningAlg("PKCS1-V1_5");

    //  SigningHashAlg is the message-digest algorithm.  The default is sha256.
    mime.put_SigningHashAlg("sha256");

    //  Micalg and Protocol are the micalg and protocol parameters written into a multipart/signed
    //  Content-Type header field.  They are normally set automatically, but can be controlled here.
    mime.put_Micalg("sha-256");
    mime.put_Protocol("application/pkcs7-signature");

    //  UseXPkcs7 controls whether newly created S/MIME media types use the historical x-pkcs7 names.
    mime.put_UseXPkcs7(false);

    //  Load a signing certificate (with private key access) from a PFX.  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;
    }

    //  Create the detached signature using the algorithms configured above.
    success = mime.AddDetachedSignature(cert);
    if (success == false) {
        std::cout << mime.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Signed with SigningAlg=" << mime.signingAlg() << " SigningHashAlg=" << mime.signingHashAlg() << "\r\n";
    }