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

void ChilkatSample(void)
    {
    BOOL success;
    HCkMimeW mime;
    const wchar_t *pfxPassword;
    HCkCertW cert;

    success = FALSE;

    mime = CkMimeW_Create();
    success = CkMimeW_SetBodyFromPlainText(mime,L"This message will be signed.");
    if (success == FALSE) {
        wprintf(L"%s\n",CkMimeW_lastErrorText(mime));
        CkMimeW_Dispose(mime);
        return;
    }

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

    //  SigningHashAlg is the message-digest algorithm.  The default is sha256.
    CkMimeW_putSigningHashAlg(mime,L"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.
    CkMimeW_putMicalg(mime,L"sha-256");
    CkMimeW_putProtocol(mime,L"application/pkcs7-signature");

    //  UseXPkcs7 controls whether newly created S/MIME media types use the historical x-pkcs7 names.
    CkMimeW_putUseXPkcs7(mime,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.
    pfxPassword = L"myPfxPassword";
    cert = CkCertW_Create();
    success = CkCertW_LoadPfxFile(cert,L"qa_data/signer.pfx",pfxPassword);
    if (success == FALSE) {
        wprintf(L"%s\n",CkCertW_lastErrorText(cert));
        CkMimeW_Dispose(mime);
        CkCertW_Dispose(cert);
        return;
    }

    //  Create the detached signature using the algorithms configured above.
    success = CkMimeW_AddDetachedSignature(mime,cert);
    if (success == FALSE) {
        wprintf(L"%s\n",CkMimeW_lastErrorText(mime));
        CkMimeW_Dispose(mime);
        CkCertW_Dispose(cert);
        return;
    }

    wprintf(L"Signed with SigningAlg=%s SigningHashAlg=%s\n",CkMimeW_signingAlg(mime),CkMimeW_signingHashAlg(mime));


    CkMimeW_Dispose(mime);
    CkCertW_Dispose(cert);

    }