C++ Requires Chilkat v11.7.0+

Choose the PDF Encryption Algorithm: AES-256, AES-128 or RC4

See more PDF Protection Examples

Demonstrates the algorithmChoice option of the encrypt operation. aes-256 is the default and the one to use unless an older reader must open the file. aes-128 is for readers that predate AES-256. rc4-128 and rc4-40 are broken ciphers kept only for very old readers. Each algorithm needs a minimum PDF version, and the file header is raised to it when the PDF is saved, never lowered. A PDF saved with RC4 is written with a classic cross-reference table so that those old readers can parse it. C++

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

    CkJsonObject json;
    CkJsonObject jsonOut;
    CkJsonObject info;

    //  AES-256, the default.  Saved as PDF 1.7 with Adobe extension level 8.
    CkPdf pdf1;
    success = pdf1.LoadFile("qa_data/pdf/two_page_memo.pdf");
    if (success == false) {
        std::cout << pdf1.lastErrorText() << "\r\n";
        return;
    }

    pdf1.put_UserPassword("user-secret");
    pdf1.put_OwnerPassword("owner-secret");
    json.UpdateString("algorithmChoice","aes-256");
    success = pdf1.Protection("encrypt",json,jsonOut);
    if (success == false) {
        std::cout << pdf1.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "aes-256 will be saved as PDF " << jsonOut.stringOf("pending.pdfVersion") << ", Adobe extension level " << jsonOut.IntOf("pending.adobeExtensionLevel") << "\r\n";
    success = pdf1.WriteFile("qa_output/memo_aes256.pdf");
    if (success == false) {
        std::cout << pdf1.lastErrorText() << "\r\n";
        return;
    }

    success = pdf1.PreLoadCheck("qa_output/memo_aes256.pdf",info);
    if (success == false) {
        std::cout << pdf1.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "  saved file: " << info.stringOf("algorithm") << ", PDF " << info.stringOf("pdfVersion") << "\r\n";

    //  AES-128, for readers that predate AES-256.  Saved as PDF 1.6.
    CkPdf pdf2;
    success = pdf2.LoadFile("qa_data/pdf/two_page_memo.pdf");
    if (success == false) {
        std::cout << pdf2.lastErrorText() << "\r\n";
        return;
    }

    pdf2.put_UserPassword("user-secret");
    pdf2.put_OwnerPassword("owner-secret");
    json.UpdateString("algorithmChoice","aes-128");
    success = pdf2.Protection("encrypt",json,jsonOut);
    if (success == false) {
        std::cout << pdf2.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "aes-128 will be saved as PDF " << jsonOut.stringOf("pending.pdfVersion") << "\r\n";
    success = pdf2.WriteFile("qa_output/memo_aes128.pdf");
    if (success == false) {
        std::cout << pdf2.lastErrorText() << "\r\n";
        return;
    }

    success = pdf2.PreLoadCheck("qa_output/memo_aes128.pdf",info);
    if (success == false) {
        std::cout << pdf2.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "  saved file: " << info.stringOf("algorithm") << ", PDF " << info.stringOf("pdfVersion") << "\r\n";

    //  RC4-128, a broken cipher, only for readers too old for AES.  Saved as PDF 1.4.
    CkPdf pdf3;
    success = pdf3.LoadFile("qa_data/pdf/two_page_memo.pdf");
    if (success == false) {
        std::cout << pdf3.lastErrorText() << "\r\n";
        return;
    }

    pdf3.put_UserPassword("user-secret");
    pdf3.put_OwnerPassword("owner-secret");
    json.UpdateString("algorithmChoice","rc4-128");
    success = pdf3.Protection("encrypt",json,jsonOut);
    if (success == false) {
        std::cout << pdf3.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "rc4-128 will be saved as PDF " << jsonOut.stringOf("pending.pdfVersion") << "\r\n";
    success = pdf3.WriteFile("qa_output/memo_rc4_128.pdf");
    if (success == false) {
        std::cout << pdf3.lastErrorText() << "\r\n";
        return;
    }

    success = pdf3.PreLoadCheck("qa_output/memo_rc4_128.pdf",info);
    if (success == false) {
        std::cout << pdf3.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "  saved file: " << info.stringOf("algorithm") << ", PDF " << info.stringOf("pdfVersion") << "\r\n";

    //  Sample output:

    //  aes-256 will be saved as PDF 1.7, Adobe extension level 8
    //    saved file: aes-256, PDF 1.7
    //  aes-128 will be saved as PDF 1.6
    //    saved file: aes-128, PDF 1.6
    //  rc4-128 will be saved as PDF 1.4
    //    saved file: rc4-128, PDF 1.4
    }