general/aes256_unicode_password

<?php

/*

 * $Id: aes256_unicode_password.php,v 1.3 2012/05/03 14:00:39 stm Exp $

 *

 * Demonstrate AES-256 encryption and Unicode passwords.

 *

 * The file can only be opened with Acrobat 9 and later.

 *

 * Required software: PDFlib/PDFlib+PDI/PPS 8

 * Required data: Norasi font

 */

$outfile = "";

$title = "AES-256 encryption and Unicode passwords";

/* This is where the data files are. Adjust as necessary. */

$searchpath = dirname(dirname(dirname(__FILE__)))."/input";

try {

    $p = new PDFlib();

    /* This means we must check return values of load_font() etc. */

    $p->set_parameter("errorpolicy", "return");

    $p->set_parameter("SearchPath", $searchpath);

    $p->set_parameter("textformat", "utf8");

    $p->set_parameter("charref", "true");

   

    /*

     * The password demonstrates some features of Unicode passwords:

     *

     * - Characters outside the normal 8-bit character range (THAI

     *   CHARACTER KO KHAI and THAI CHARACTER KHO KAI)

     *   

     * - Normalization of Unicode passwords (LATIN SMALL LIGATURE FF

     *   and LATIN SMALL LIGATURE FI are normalized to "ff" and "fi")

     */

    $thai_letters = "\xE0\xB8\x81\xE0\xB8\x82";

    $ligatures = "\xEF\xAC\x80 \xEF\xAC\x81";

    $normalized_ligatures ="ff fi";

   

    $password = $thai_letters . " " . $ligatures;

    $normalized_password = $thai_letters . " "

                                . $normalized_ligatures;

    /*

     * To get AES-256 encryption the PDF version must be set to

     * PDF 1.7 extension level 3.

     */

    $optlist = "compatibility=1.7ext3 "

            . "masterpassword={\xEF\xBB\xBF" . $password . "}";

    if ($p->begin_document($outfile, $optlist) == 0)

        throw new Exception("Error: " . $p->get_errmsg());

    $p->set_info("Creator", "PDFlib Cookbook");

    $p->set_info("Title", $title );

    $p->begin_page_ext(595, 842, "");

    $font = $p->load_font("Norasi", "unicode", "embedding");

    if ($font == 0)

        throw new Exception("Error: " . $p->get_errmsg());

    $p->setfont($font, 24);

    $p->set_text_pos(50, 700);

    $p->show("AES-256 encryption and Unicode passwords");

   

    $text =

        "This document produced by PDFlib is AES-256-encrypted. It "

        . "can only be opened by Acrobat 9 and later.\n\n"

        . "The master password of this document is:\n\n"

        . $password

        . "\n\nUse cut&paste to enter the password into the Acrobat "

        . "prompt for changing the security settings of the document.\n\n"

        . "Because the password is normalized, it can also be "

        . "entered like this (note the decomposed ligatures):\n\n"

        . $normalized_password;

    $tf = $p->add_textflow(0, $text,

        "fontname=Norasi fontsize=18 encoding=unicode");

    if ($tf == 0)

        throw new Exception("Error: " . $p->get_errmsg());

    $p->fit_textflow($tf, 50, 50, 500, 650, "");

   

    $p->end_page_ext("");

    $p->end_document("");

    $buf = $p->get_buffer();

    $len = strlen($buf);

    header("Content-type: application/pdf");

    header("Content-Length: $len");

    header("Content-Disposition: inline; filename=starter_basic.pdf");

    print $buf;

}

catch (PDFlibException $e) {

    die("PDFlib exception occurred:\n" . 

        "[" . $e->get_errnum() . "] " . $e->get_apiname() . ": " .

        $e->get_errmsg() . "\n");

}

catch (Exception $e) {

    die($e);

}

$p = 0;

?>