C++ Requires Chilkat v11.7.0+

Password-Protect a PDF with AES-256 Encryption

See more PDF Protection Examples

Demonstrates the simplest way to encrypt a PDF so that it needs a password to open. The passwords come from the UserPassword and OwnerPassword properties, and Protection with the encrypt operation and an empty JSON uses the defaults: AES-256, everything encrypted, every permission granted. Protection only records the security the PDF will be saved with. Nothing is encrypted until WriteFile is called. C++

#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

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

    //  The passwords are taken from these two properties at the time Protection is called.
    //  The user password opens the PDF.  The owner password opens it too, and is the one needed
    //  later to change or remove the protection.
    pdf.put_UserPassword("user-secret");
    pdf.put_OwnerPassword("owner-secret");

    //  An empty JSON asks for the defaults: AES-256, everything encrypted, every permission granted.
    CkJsonObject json;
    CkJsonObject jsonOut;
    success = pdf.Protection("encrypt",json,jsonOut);
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    //  Nothing has been encrypted yet.  "pending" describes the security the PDF will be saved with.
    std::cout << "algorithm: " << jsonOut.stringOf("pending.algorithm") << "\r\n";
    std::cout << "PDF version: " << jsonOut.stringOf("pending.pdfVersion") << "\r\n";
    std::cout << "password needed to open: " << jsonOut.BoolOf("pending.userPasswordRequired") << "\r\n";

    //  Writing the file applies it.
    success = pdf.WriteFile("qa_output/memo_encrypted.pdf");
    if (success == false) {
        std::cout << pdf.lastErrorText() << "\r\n";
        return;
    }

    //  PreLoadCheck reports a file's encryption without loading it, and needs no password.
    CkPdf checker;
    CkJsonObject info;
    success = checker.PreLoadCheck("qa_output/memo_encrypted.pdf",info);
    if (success == false) {
        std::cout << checker.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "encrypted: " << info.BoolOf("encrypted") << "\r\n";
    std::cout << "openPasswordRequired: " << info.BoolOf("openPasswordRequired") << "\r\n";

    //  With the password, the PDF opens normally.
    CkPdf reader;
    reader.put_UserPassword("user-secret");
    success = reader.LoadFile("qa_output/memo_encrypted.pdf");
    if (success == false) {
        std::cout << reader.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "pages: " << reader.get_NumPages() << "\r\n";

    //  Sample output:

    //  algorithm: aes-256
    //  PDF version: 1.7
    //  password needed to open: True
    //  encrypted: True
    //  openPasswordRequired: True
    //  pages: 2
    }