(C++) Sign a Byte Array to Create an Opaque Signature in a Byte Array

Signs data contained in a byte array to produce an opaque signature (also in a byte array). An opaque signature is a PKCS7 signature (also known as CAdES) that embeds the signed data. Also shows how to verify the signature and extract the original data.

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#include <CkCert.h>
#include <CkFileAccess.h>
#include <CkByteData.h>
#include <CkCrypt2.h>

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

    CkCert cert;
    bool success = cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123");
    if (success == false) {
        std::cout << cert.lastErrorText() << "\r\n";
        return;
    }

    CkFileAccess fac;

    CkByteData fileBytes;
    success = fac.ReadEntireFile("qa_data/pdf/sample.pdf",fileBytes);
    if (fac.get_LastMethodSuccess() != true) {
        std::cout << fac.lastErrorText() << "\r\n";
        return;
    }

    CkCrypt2 crypt;

    success = crypt.SetSigningCert(cert);

    // We can sign any type of file.

    CkByteData sigBytes;
    success = crypt.OpaqueSignBytes(fileBytes,sigBytes);
    if (crypt.get_LastMethodSuccess() != true) {
        std::cout << crypt.lastErrorText() << "\r\n";
        return;
    }

    success = fac.WriteEntireFile("qa_output/sample.pdf.p7m",sigBytes);
    if (fac.get_LastMethodSuccess() != true) {
        std::cout << fac.lastErrorText() << "\r\n";
        return;
    }

    // We can verify the opaque signature and extract the original data like this
    CkByteData originalData;
    success = crypt.OpaqueVerifyBytes(sigBytes,originalData);
    if (crypt.get_LastMethodSuccess() != true) {
        std::cout << crypt.lastErrorText() << "\r\n";
        return;
    }

    success = fac.WriteEntireFile("qa_output/sample.pdf",originalData);
    if (fac.get_LastMethodSuccess() != true) {
        std::cout << fac.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Signature is verified and the original data was extracted." << "\r\n";
    }