C++ Requires Chilkat v11.7.0+

Encrypt a PDF for a Certificate Instead of a Password

See more PDF Protection Examples

Demonstrates certificate security, where a PDF is encrypted for one or more recipients and each opens it with their own certificate and private key. No password is involved. Only the public certificate of a recipient is needed to encrypt. Each recipient has its own permissions, and the changeSecurity permission gives a recipient owner rights. PreLoadCheck tells an application that a file is certificate-encrypted and which certificates can open it. A PDF that cannot be opened, because no matching certificate and private key were provided, fails to load. C++

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

void ChilkatSample(void)
    {
    bool success = false;

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

    //  The PDF used in this example is available at two_page_memo.pdf

    //  The recipient's certificate.  Only the public certificate is needed to encrypt.
    CkCert recipient;
    success = recipient.LoadFromFile("qa_data/certs/recipient.cer");
    if (success == false) {
        std::cout << recipient.lastErrorText() << "\r\n";
        return;
    }

    CkPdf pdf;
    success = pdf.LoadFile("qa_data/pdf/two_page_memo.pdf");
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    //  Call AddEncryptCert once for each recipient.
    success = pdf.AddEncryptCert(recipient);
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    //  recipientPermissions[0] belongs to the first certificate added.  changeSecurity gives that
    //  recipient owner rights, so the file can be managed later.
    CkJsonObject json;
    json.UpdateString("method","certificate");
    json.UpdateBool("recipientPermissions[0].changeSecurity",true);

    CkJsonObject jsonOut;
    success = pdf.Protection("encrypt",json,jsonOut);
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "method: " << jsonOut.stringOf("pending.method") << "\r\n";
    std::cout << "algorithm: " << jsonOut.stringOf("pending.algorithm") << "\r\n";
    std::cout << "recipients: " << jsonOut.SizeOfArray("pending.recipients") << "\r\n";

    success = pdf.WriteFile("qa_output/memo_for_recipient.pdf");
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    //  PreLoadCheck says how the file is protected, without loading it.
    CkPdf reader;
    CkJsonObject info;
    success = reader.PreLoadCheck("qa_output/memo_for_recipient.pdf",info);
    if (success == false) {
        std::cout << reader.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "saved file, method: " << info.stringOf("method") << "\r\n";
    std::cout << "saved file, recipients: " << info.SizeOfArray("recipients") << "\r\n";

    //  The recipient opens it with the certificate and its private key, here from a .pfx file.
    //  (On Windows, a certificate that is installed in the Windows certificate store with its private
    //  key is found automatically when the PDF is loaded, and SetDecryptCert is not needed for it.)
    CkCert myCert;
    success = myCert.LoadPfxFile("qa_data/pfx/recipient.pfx","pfx-password");
    if (success == false) {
        std::cout << myCert.lastErrorText() << "\r\n";
        return;
    }

    success = reader.SetDecryptCert(myCert);
    if (success == false) {
        std::cout << reader.lastErrorText() << "\r\n";
        return;
    }

    success = reader.LoadFile("qa_output/memo_for_recipient.pdf");
    if (success == false) {
        std::cout << reader.lastErrorText() << "\r\n";
        return;
    }

    CkJsonObject empty;
    CkJsonObject loadedInfo;
    success = reader.Protection("getInfo",empty,loadedInfo);
    if (success == false) {
        std::cout << reader.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "opened with: " << loadedInfo.stringOf("loaded.openedWith") << "\r\n";
    std::cout << "pages: " << reader.get_NumPages() << "\r\n";

    //  Sample output:

    //  method: certificate
    //  algorithm: aes-256
    //  recipients: 1
    //  saved file, method: certificate
    //  saved file, recipients: 1
    //  opened with: certificate
    //  pages: 2
    }