Java 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. Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean 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 = new CkJsonObject();
    CkJsonObject jsonOut = new CkJsonObject();
    CkJsonObject info = new CkJsonObject();

    //  AES-256, the default.  Saved as PDF 1.7 with Adobe extension level 8.
    CkPdf pdf1 = new CkPdf();
    success = pdf1.LoadFile("qa_data/pdf/two_page_memo.pdf");
    if (success == false) {
        System.out.println(pdf1.lastErrorText());
        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) {
        System.out.println(pdf1.lastErrorText());
        return;
        }

    System.out.println("aes-256 will be saved as PDF " + jsonOut.stringOf("pending.pdfVersion") + ", Adobe extension level " + jsonOut.IntOf("pending.adobeExtensionLevel"));
    success = pdf1.WriteFile("qa_output/memo_aes256.pdf");
    if (success == false) {
        System.out.println(pdf1.lastErrorText());
        return;
        }

    success = pdf1.PreLoadCheck("qa_output/memo_aes256.pdf",info);
    if (success == false) {
        System.out.println(pdf1.lastErrorText());
        return;
        }

    System.out.println("  saved file: " + info.stringOf("algorithm") + ", PDF " + info.stringOf("pdfVersion"));

    //  AES-128, for readers that predate AES-256.  Saved as PDF 1.6.
    CkPdf pdf2 = new CkPdf();
    success = pdf2.LoadFile("qa_data/pdf/two_page_memo.pdf");
    if (success == false) {
        System.out.println(pdf2.lastErrorText());
        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) {
        System.out.println(pdf2.lastErrorText());
        return;
        }

    System.out.println("aes-128 will be saved as PDF " + jsonOut.stringOf("pending.pdfVersion"));
    success = pdf2.WriteFile("qa_output/memo_aes128.pdf");
    if (success == false) {
        System.out.println(pdf2.lastErrorText());
        return;
        }

    success = pdf2.PreLoadCheck("qa_output/memo_aes128.pdf",info);
    if (success == false) {
        System.out.println(pdf2.lastErrorText());
        return;
        }

    System.out.println("  saved file: " + info.stringOf("algorithm") + ", PDF " + info.stringOf("pdfVersion"));

    //  RC4-128, a broken cipher, only for readers too old for AES.  Saved as PDF 1.4.
    CkPdf pdf3 = new CkPdf();
    success = pdf3.LoadFile("qa_data/pdf/two_page_memo.pdf");
    if (success == false) {
        System.out.println(pdf3.lastErrorText());
        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) {
        System.out.println(pdf3.lastErrorText());
        return;
        }

    System.out.println("rc4-128 will be saved as PDF " + jsonOut.stringOf("pending.pdfVersion"));
    success = pdf3.WriteFile("qa_output/memo_rc4_128.pdf");
    if (success == false) {
        System.out.println(pdf3.lastErrorText());
        return;
        }

    success = pdf3.PreLoadCheck("qa_output/memo_rc4_128.pdf",info);
    if (success == false) {
        System.out.println(pdf3.lastErrorText());
        return;
        }

    System.out.println("  saved file: " + info.stringOf("algorithm") + ", PDF " + info.stringOf("pdfVersion"));

    //  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
  }
}