(MFC) Sign a File to Create a .p7s (Detached Signature)

MFC example to create a detached signature file (.p7s) for any type file. The signature can be verified by calling VerifyP7S and passing the original filename and the .p7s filename.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkCrypt2.h>
#include <CkCertStore.h>
#include <CkCert.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkCrypt2 crypt;

    // Use a digital certificate and private key from a PFX file (.pfx or .p12).
    const char *signingCertSubject = "Acme Inc";
    const char *pfxFilename = "/Users/chilkat/testData/pfx/acme.pfx";
    const char *pfxPassword = "test123";

    CkCertStore certStore;
    bool success = certStore.LoadPfxFile(pfxFilename,pfxPassword);
    if (success != true) {
        strOut.append(certStore.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkCert *cert = certStore.FindCertBySubjectCN(signingCertSubject);
    if (certStore.get_LastMethodSuccess() == false) {
        strOut.append("Failed to find certificate by subject common name.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Tell the crypt component to use this cert.
    success = crypt.SetSigningCert(*cert);

    // We can sign any type of file, creating a .p7s as output:
    const char *inFile = "/Users/chilkat/testData/pdf/sample.pdf";
    const char *sigFile = "/Users/chilkat/testData/p7s/sample.p7s";

    success = crypt.CreateP7S(inFile,sigFile);
    if (success == false) {
        strOut.append(crypt.lastErrorText());
        strOut.append("\r\n");
        delete cert;
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    success = crypt.VerifyP7S(inFile,sigFile);
    if (success == false) {
        strOut.append(crypt.lastErrorText());
        strOut.append("\r\n");
        delete cert;
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    delete cert;

    strOut.append("Success!");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }