Unicode 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. Unicode C++

#include <CkCertW.h>
#include <CkPdfW.h>
#include <CkJsonObjectW.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.
    CkCertW recipient;
    success = recipient.LoadFromFile(L"qa_data/certs/recipient.cer");
    if (success == false) {
        wprintf(L"%s\n",recipient.lastErrorText());
        return;
    }

    CkPdfW pdf;
    success = pdf.LoadFile(L"qa_data/pdf/two_page_memo.pdf");
    if (success == false) {
        wprintf(L"%s\n",pdf.lastErrorText());
        return;
    }

    //  Call AddEncryptCert once for each recipient.
    success = pdf.AddEncryptCert(recipient);
    if (success == false) {
        wprintf(L"%s\n",pdf.lastErrorText());
        return;
    }

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

    CkJsonObjectW jsonOut;
    success = pdf.Protection(L"encrypt",json,jsonOut);
    if (success == false) {
        wprintf(L"%s\n",pdf.lastErrorText());
        return;
    }

    wprintf(L"method: %s\n",jsonOut.stringOf(L"pending.method"));
    wprintf(L"algorithm: %s\n",jsonOut.stringOf(L"pending.algorithm"));
    wprintf(L"recipients: %d\n",jsonOut.SizeOfArray(L"pending.recipients"));

    success = pdf.WriteFile(L"qa_output/memo_for_recipient.pdf");
    if (success == false) {
        wprintf(L"%s\n",pdf.lastErrorText());
        return;
    }

    //  PreLoadCheck says how the file is protected, without loading it.
    CkPdfW reader;
    CkJsonObjectW info;
    success = reader.PreLoadCheck(L"qa_output/memo_for_recipient.pdf",info);
    if (success == false) {
        wprintf(L"%s\n",reader.lastErrorText());
        return;
    }

    wprintf(L"saved file, method: %s\n",info.stringOf(L"method"));
    wprintf(L"saved file, recipients: %d\n",info.SizeOfArray(L"recipients"));

    //  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.)
    CkCertW myCert;
    success = myCert.LoadPfxFile(L"qa_data/pfx/recipient.pfx",L"pfx-password");
    if (success == false) {
        wprintf(L"%s\n",myCert.lastErrorText());
        return;
    }

    success = reader.SetDecryptCert(myCert);
    if (success == false) {
        wprintf(L"%s\n",reader.lastErrorText());
        return;
    }

    success = reader.LoadFile(L"qa_output/memo_for_recipient.pdf");
    if (success == false) {
        wprintf(L"%s\n",reader.lastErrorText());
        return;
    }

    CkJsonObjectW empty;
    CkJsonObjectW loadedInfo;
    success = reader.Protection(L"getInfo",empty,loadedInfo);
    if (success == false) {
        wprintf(L"%s\n",reader.lastErrorText());
        return;
    }

    wprintf(L"opened with: %s\n",loadedInfo.stringOf(L"loaded.openedWith"));
    wprintf(L"pages: %d\n",reader.get_NumPages());

    //  Sample output:

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