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Friday, June 13, 2008

PDF Protection

Informations


Author: Klemen Vodopivec

License: Freeware

Description


This script allows to protect the PDF, that is to say prevent people from copying its content, print it or modify it.



SetProtection([array permissions [, string user_pass [, string owner_pass]]])



permissions: the set of permissions. Empty by default (only viewing is allowed).

user_pass: user password. Empty by default.

owner_pass: owner password. If not specified, a random value is used.



The permission array is composed of values taken from the following ones:




  • copy: copy text and images to the clipboard

  • print: print the document

  • modify: modify it (except for annotations and forms)

  • annot-forms: add annotations and forms


Remark: the protection against modification is for people who have the full Acrobat product.



If you don't set any password, the document will open as usual. If you set a user password, the PDF viewer will ask for it before displaying the document. The master password, if different from the user one, can be used to get full access.



Note: protecting a document requires to encrypt it, which increases the processing time a lot. This can cause a PHP time-out in some cases, especially if the document contains images or fonts.

Source








<?php

/****************************************************************************

* Software: FPDF_Protection                                                 *

* Version:  1.02                                                            *

* Date:     2005/05/08                                                      *

* Author:   Klemen VODOPIVEC                                                *

* License:  Freeware                                                        *

*                                                                           *

* You may use and modify this software as you wish as stated in original    *

* FPDF package.                                                             *

*                                                                           *

* Thanks: Cpdf (http://www.ros.co.nz/pdf) was my working sample of how to   *

* implement protection in pdf.                                              *

****************************************************************************/



require('fpdf.php');



class FPDF_Protection extends FPDF

{

    var $encrypted;          //whether document is protected

    var $Uvalue;             //U entry in pdf document

    var $Ovalue;             //O entry in pdf document

    var $Pvalue;             //P entry in pdf document

    var $enc_obj_id;         //encryption object id

    var $last_rc4_key;       //last RC4 key encrypted (cached for optimisation)

    var $last_rc4_key_c;     //last RC4 computed key



    function FPDF_Protection($orientation='P',$unit='mm',$format='A4')

    {

        parent::FPDF($orientation,$unit,$format);



        $this->encrypted=false;

        $this->last_rc4_key='';

        $this->padding="\x28\xBF\x4E\x5E\x4E\x75\x8A\x41\x64\x00\x4E\x56\xFF\xFA\x01\x08".

                        "\x2E\x2E\x00\xB6\xD0\x68\x3E\x80\x2F\x0C\xA9\xFE\x64\x53\x69\x7A";

    }



    /**

    * Function to set permissions as well as user and owner passwords

    *

    * - permissions is an array with values taken from the following list:

    *   copy, print, modify, annot-forms

    *   If a value is present it means that the permission is granted

    * - If a user password is set, user will be prompted before document is opened

    * - If an owner password is set, document can be opened in privilege mode with no

    *   restriction if that password is entered

    */

    function SetProtection($permissions=array(),$user_pass='',$owner_pass=null)

    {

        $options = array('print' => 4, 'modify' => 8, 'copy' => 16, 'annot-forms' => 32 );

        $protection = 192;

        foreach($permissions as $permission){

            if (!isset($options[$permission]))

                $this->Error('Incorrect permission: '.$permission);

            $protection += $options[$permission];

        }

        if ($owner_pass === null)

            $owner_pass = uniqid(rand());

        $this->encrypted = true;

        $this->_generateencryptionkey($user_pass, $owner_pass, $protection);

    }



/****************************************************************************

*                                                                           *

*                              Private methods                              *

*                                                                           *

****************************************************************************/



    function _putstream($s)

    {

        if ($this->encrypted) {

            $s = $this->_RC4($this->_objectkey($this->n), $s);

        }

        parent::_putstream($s);

    }



    function _textstring($s)

    {

        if ($this->encrypted) {

            $s = $this->_RC4($this->_objectkey($this->n), $s);

        }

        return parent::_textstring($s);

    }



    /**

    * Compute key depending on object number where the encrypted data is stored

    */

    function _objectkey($n)

    {

        return substr($this->_md5_16($this->encryption_key.pack('VXxx',$n)),0,10);

    }



    /**

    * Escape special characters

    */

    function _escape($s)

    {

        $s=str_replace('\\','\\\\',$s);

        $s=str_replace(')','\\)',$s);

        $s=str_replace('(','\\(',$s);

        $s=str_replace("\r",'\\r',$s);

        return $s;

    }



    function _putresources()

    {

        parent::_putresources();

        if ($this->encrypted) {

            $this->_newobj();

            $this->enc_obj_id = $this->n;

            $this->_out('<<');

            $this->_putencryption();

            $this->_out('>>');

            $this->_out('endobj');

        }

    }



    function _putencryption()

    {

        $this->_out('/Filter /Standard');

        $this->_out('/V 1');

        $this->_out('/R 2');

        $this->_out('/O ('.$this->_escape($this->Ovalue).')');

        $this->_out('/U ('.$this->_escape($this->Uvalue).')');

        $this->_out('/P '.$this->Pvalue);

    }



    function _puttrailer()

    {

        parent::_puttrailer();

        if ($this->encrypted) {

            $this->_out('/Encrypt '.$this->enc_obj_id.' 0 R');

            $this->_out('/ID [()()]');

        }

    }



    /**

    * RC4 is the standard encryption algorithm used in PDF format

    */

    function _RC4($key, $text)

    {

        if ($this->last_rc4_key != $key) {

            $k = str_repeat($key, 256/strlen($key)+1);

            $rc4 = range(0,255);

            $j = 0;

            for ($i=0; $i<256; $i++){

                $t = $rc4[$i];

                $j = ($j + $t + ord($k{$i})) % 256;

                $rc4[$i] = $rc4[$j];

                $rc4[$j] = $t;

            }

            $this->last_rc4_key = $key;

            $this->last_rc4_key_c = $rc4;

        } else {

            $rc4 = $this->last_rc4_key_c;

        }



        $len = strlen($text);

        $a = 0;

        $b = 0;

        $out = '';

        for ($i=0; $i<$len; $i++){

            $a = ($a+1)%256;

            $t= $rc4[$a];

            $b = ($b+$t)%256;

            $rc4[$a] = $rc4[$b];

            $rc4[$b] = $t;

            $k = $rc4[($rc4[$a]+$rc4[$b])%256];

            $out.=chr(ord($text{$i}) ^ $k);

        }



        return $out;

    }



    /**

    * Get MD5 as binary string

    */

    function _md5_16($string)

    {

        return pack('H*',md5($string));

    }



    /**

    * Compute O value

    */

    function _Ovalue($user_pass, $owner_pass)

    {

        $tmp = $this->_md5_16($owner_pass);

        $owner_RC4_key = substr($tmp,0,5);

        return $this->_RC4($owner_RC4_key, $user_pass);

    }



    /**

    * Compute U value

    */

    function _Uvalue()

    {

        return $this->_RC4($this->encryption_key, $this->padding);

    }



    /**

    * Compute encryption key

    */

    function _generateencryptionkey($user_pass, $owner_pass, $protection)

    {

        // Pad passwords

        $user_pass = substr($user_pass.$this->padding,0,32);

        $owner_pass = substr($owner_pass.$this->padding,0,32);

        // Compute O value

        $this->Ovalue = $this->_Ovalue($user_pass,$owner_pass);

        // Compute encyption key

        $tmp = $this->_md5_16($user_pass.$this->Ovalue.chr($protection)."\xFF\xFF\xFF");

        $this->encryption_key = substr($tmp,0,5);

        // Compute U value

        $this->Uvalue = $this->_Uvalue();

        // Compute P value

        $this->Pvalue = -(($protection^255)+1);

    }

}



?>

Example


This example shows how to allow only printing.









<?php

define('FPDF_FONTPATH','font/');

require('fpdf_protection.php');



$pdf=new FPDF_Protection();

$pdf->SetProtection(array('print'));

$pdf->Open();

$pdf->AddPage();

$pdf->SetFont('Arial');

$pdf->Write(10,'You can print me but not copy my text.');

$pdf->Output();

?>



View the result here.

Download


ZIP | TGZ
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Tuesday, June 10, 2008

Get metadata on MySQL databases

Getting information about databases if essential if you want to write generic and scalable applications. This code shows you how to get information such as all databases on the server, all tables in each database and all field and field info for each table. Even if you do not need to build on this code, you might want to copy the code which prints out all databases, tables and field information plus examples. Its a great way to get an overview of the tables you are working on for a project.

<?

//getting metadata on MySQL databases



//output the structure of a table

$connection_1 = mysql_connect("localhost");

$fields = mysql_list_fields("cmphp","rights");

for($i=0;$i<mysql_num_fields($fields);$i++) {

   echo mysql_field_name($fields,$i)." (".mysql_field_len($fields,$i).") - ".mysql_field_type($fields,$i)."<br>";

}

mysql_close;



//show the structure of ALL tables in ALL databases on the server

$server_connection_1 = mysql_connect("localhost");

$databases = mysql_query("SHOW DATABASES");

while($database = mysql_fetch_row($databases)) {

   echo '<h2>DATABASE: '.$database[0].'</h2>';

   $database_connection_1 = mysql_select_db($database[0]);

   $tables = mysql_query("SHOW TABLES");

   while($table = mysql_fetch_row($tables)){

       echo '<table border="1" cellpadding="5" width="500">';

       echo '<tr><td colspan="3" bgcolor="silver">TABLE: '.$table[0].'</td></tr>';

       $fields = mysql_list_fields($database[0],$table[0]);

       for($i=0;$i<mysql_num_fields($fields);$i++) {

           echo '<tr>';

           echo '<td>'.mysql_field_name($fields,$i)."</td>";

           echo '<td>'.mysql_field_len($fields,$i)."</td>";

           echo '<td>'.mysql_field_type($fields,$i)."</td>";

           echo '</tr>';

       }

       echo '</table><br>';

   }

}

mysql_close;



//show the nice structure of a particular database

$server_connection_1 = mysql_connect("localhost");

$the_database = "cmphp";

echo '<h2>DATABASE: '.$the_database.'</h2>';

$database_connection_1 = mysql_select_db($the_database);

$tables = mysql_query("SHOW TABLES");

while($table = mysql_fetch_row($tables)){

   echo '<table border="1" cellpadding="5" width="600">';

   echo '<tr><td colspan="4" bgcolor="silver"><b>TABLE: '.$table[0].'</b></td></tr>';

   echo '<tr><td bgcolor="silver">NAME</td><td bgcolor="silver">SIZE</td><td bgcolor="silver">TYPE</td><td bgcolor="silver">EXAMPLE</td></tr>';

   $fields = mysql_list_fields($the_database,$table[0]);

   for($i=0;$i<mysql_num_fields($fields);$i++) {

       echo '<tr>';

       echo '<td>'.mysql_field_name($fields,$i)."</td>";

       echo '<td>'.mysql_field_len($fields,$i)."</td>";

       echo '<td>'.mysql_field_type($fields,$i)."</td>";

       $rows = mysql_query("SELECT ".mysql_field_name($fields,$i)." FROM ".$table[0]." LIMIT 1");

       $row = mysql_fetch_array($rows);

       echo '<td bgcolor="eeeeee">'.$row[0].' </td>';

       echo '</tr>';

   }

   echo '</table><br>';

}

mysql_close;

?>

This Article is taken from http://www.developerfusion.co.uk/show/3945/
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