XVI. Crack Functions

Introduction

These functions allow you to use the CrackLib library to test the 'strength' of a password. The 'strength' of a password is tested by that checks length, use of upper and lower case and checked against the specified CrackLib dictionary. CrackLib will also give helpful diagnostic messages that will help 'strengthen' the password.

Note: This extension has been moved to the PECL repository and is no longer bundled with PHP as of PHP 5.0.0.

Requirements

More information regarding CrackLib along with the library can be found at http://sourceforge.net/projects/cracklib.

Installation

This PECL extension is not bundled with PHP. Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: http://pecl.php.net/package/crack.

In PHP 4 this PECL extensions source can be found in the ext/ directory within the PHP source or at the PECL link above. In order to use these functions you must compile PHP with Crack support by using the --with-crack[=DIR] configuration option.

Windows users will enable php_crack.dll inside of php.ini in order to use these functions. In PHP 4 this DLL resides in the extensions/ directory within the PHP Windows binaries download. The DLL for this PECL extension may be downloaded from either the PHP Downloads page or from http://pecl4win.php.net/

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 1. Crack configuration options

Name	Default	Changeable	Changelog
crack.default_dictionary	NULL	PHP_INI_PERDIR	Available since PHP 4.0.5.

For further details and definitions of the PHP_INI_* constants, see the Appendix I.

Resource Types

The CrackLib extension defines a dictionary resource identifier returned by crack_opendict().

Predefined Constants

This extension has no constants defined.

Examples

This example shows how to open a CrackLib dictionary, test a given password, retrieve any diagnostic messages, and close the dictionary.

Example 1. CrackLib example


<?php
// Open CrackLib Dictionary
$dictionary = crack_opendict('/usr/local/lib/pw_dict')
     or die('Unable to open CrackLib dictionary');

// Perform password check
$check = crack_check($dictionary, 'gx9A2s0x');

// Retrieve messages
$diag = crack_getlastmessage();
echo $diag; // 'strong password'

// Close dictionary
crack_closedict($dictionary);
?>

Note: If crack_check() returns TRUE, crack_getlastmessage() will return 'strong password'.

Table of Contents
crack_check -- Performs an obscure check with the given password
crack_closedict -- Closes an open CrackLib dictionary
crack_getlastmessage -- Returns the message from the last obscure check
crack_opendict -- Opens a new CrackLib dictionary