(MFC) PKCS11 Sign PDF using Certificate and Private Key on Smart Card / USB Token

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Sample code showing how to use PKCS11 to sign a PDF with a certificate and private key stored on a smart card or USB token.

Note: This example requires Chilkat v9.5.0.88 or later.

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

See Also: Using MFC CString in Chilkat

#include <CkPkcs11.h>
#include <CkJsonObject.h>
#include <CkCert.h>
#include <CkPdf.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    // Note: Chilkat's PKCS11 implementation runs on Windows, Linux, Mac OS X, and other supported operating systems.

    CkPkcs11 pkcs11;

    // This example is tested on Windows using a Giesecke and Devrient Sm@rtCafe Expert 3.2 smart card.
    pkcs11.put_SharedLibPath("aetpkss1.dll");

    bool success = pkcs11.Initialize();
    if (success == false) {
        strOut.append(pkcs11.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // We need to call Discover to get the slot ID.
    bool onlyTokensPresent = true;
    CkJsonObject jsonPkcs11;
    success = pkcs11.Discover(onlyTokensPresent,jsonPkcs11);
    if (success == false) {
        strOut.append(pkcs11.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Make sure we have at least one slot.
    if (jsonPkcs11.SizeOfArray("slot") <= 0) {
        strOut.append("No occuplied slots.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Get the ID of the 1st slot
    int slotID = jsonPkcs11.IntOf("slot[0].id");

    // Open a session.
    bool readWrite = true;
    success = pkcs11.OpenSession(slotID,readWrite);
    if (success == false) {
        strOut.append(pkcs11.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Make it an authenticated session by calling Login.
    int userType = 1;
    // Make sure to use the correct PIN for your smart card..
    const char *pin = "0000";
    success = pkcs11.Login(userType,pin);
    if (success == false) {
        strOut.append(pkcs11.lastErrorText());
        strOut.append("\r\n");
        success = pkcs11.CloseSession();
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Get the certificate (on the smart card) that has a private key.
    CkCert cert;
    success = pkcs11.FindCert("privateKey","",cert);
    if (success == true) {
        strOut.append("Cert with private key: ");
        strOut.append(cert.subjectCN());
        strOut.append("\r\n");
    }
    else {
        strOut.append("No certificates having a private key were found.");
        strOut.append("\r\n");
        success = pkcs11.CloseSession();
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // --------------------------------------------------------------------------
    // At this point, we have the cert to be used for signing.
    // Our PDF signing code is the same as for a cert obtained from any other source..

    CkPdf pdf;

    // Load a PDF to be signed.
    success = pdf.LoadFile("qa_data/pdf/hello.pdf");
    if (success == false) {
        strOut.append(pdf.lastErrorText());
        strOut.append("\r\n");
        success = pkcs11.CloseSession();
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkJsonObject json;

    json.UpdateInt("page",1);
    json.UpdateString("appearance.y","top");
    json.UpdateString("appearance.x","left");
    json.UpdateString("appearance.fontScale","10.0");
    json.UpdateString("signingAlgorithm","pss");
    json.UpdateString("hashAlgorithm","sha256");

    int i = 0;
    json.put_I(i);
    json.UpdateString("appearance.text[i]","Digitaly signed by: Xyz Widgets, Inc.");
    i = i + 1;
    json.put_I(i);
    json.UpdateString("appearance.text[i]","current_dt");
    i = i + 1;
    json.put_I(i);
    json.UpdateString("appearance.text[i]","blah blah blah");

    // The certificate is internally linked to the Pkcs11 object, which is currently in an authenticated session.
    success = pdf.SetSigningCert(cert);

    success = pdf.SignPdf(json,"qa_output/out.pdf");
    if (success == false) {
        strOut.append(pdf.lastErrorText());
        strOut.append("\r\n");
        success = pkcs11.CloseSession();
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // --------------------------------------------------------------------------

    // Revert to an unauthenticated session by calling Logout.
    success = pkcs11.Logout();
    if (success == false) {
        strOut.append(pkcs11.lastErrorText());
        strOut.append("\r\n");
        success = pkcs11.CloseSession();
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // When finished, close the session.
    // It is important to close the session (memory leaks will occur if the session is not properly closed).
    success = pkcs11.CloseSession();
    if (success == false) {
        strOut.append(pkcs11.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

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


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }