(Unicode C++) CoSign PKCS7/CMS Signed Data

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Demonstrates how to add a 2nd signature to a CMS SignedData. This is to add an additional signature, SignerInfo and certificate(s) to an existing CMS signed data.

In this example, we cosign an existing pdf.p7s

Note: The CoSign method is added in Chilkat v9.5.0.89.

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#include <CkCrypt2W.h>
#include <CkCertW.h>
#include <CkBinDataW.h>

void ChilkatSample(void)
    {
    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkCrypt2W crypt;
    CkCertW cert;

    // If loading from a smart card, set the smartcard PIN.
    cert.put_SmartCardPin(L"0000");

    // Load a certificate in some way, such as from a smart card.
    // Chilkat provides other methods to load from a .pfx, .pem, or from the Windows certificate stores..
    bool success = cert.LoadFromSmartcard(L"");
    if (success == false) {
        wprintf(L"%s\n",cert.lastErrorText());
        return;
    }

    success = crypt.SetSigningCert(cert);
    if (success == false) {
        wprintf(L"%s\n",crypt.lastErrorText());
        return;
    }

    // Load the file to be co-signed.
    // NOTE:  This is to cosign a PDF file contained within a CMS (PKCS7) message.
    // (In other words, the PDF is contained within the CMS SignedData, rather than the other way around
    // where a CMS signature is contained within a PDF.  Use Chilkat's PDF class to sign a PDF, which is
    // to embed a CMS signature within the PDF.)
    CkBinDataW bd;
    success = bd.LoadFile(L"qa_data/p7s/cosign/sample.pdf.p7s");
    if (success == false) {
        wprintf(L"Failed to load pdf.p7s input file.\n");
        return;
    }

    // bd2 will contain the co-signed result.
    CkBinDataW bd2;
    success = crypt.CoSign(bd,cert,bd2);
    if (success == false) {
        wprintf(L"%s\n",crypt.lastErrorText());
        return;
    }

    success = bd.WriteFile(L"qa_output/cosigned.pdf.p7s");
    if (success == false) {
        wprintf(L"Failed to save pdf.p7s output file.\n");
        return;
    }

    wprintf(L"Success!\n");
    }