--- /dev/null
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<head>
+
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+<title>Encryption Class : CodeIgniter User Guide</title>
+
+<style type='text/css' media='all'>@import url('../userguide.css');</style>
+<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' />
+
+<script type="text/javascript" src="../nav/nav.js"></script>
+<script type="text/javascript" src="../nav/prototype.lite.js"></script>
+<script type="text/javascript" src="../nav/moo.fx.js"></script>
+<script type="text/javascript" src="../nav/user_guide_menu.js"></script>
+
+<meta http-equiv='expires' content='-1' />
+<meta http-equiv= 'pragma' content='no-cache' />
+<meta name='robots' content='all' />
+<meta name='author' content='ExpressionEngine Dev Team' />
+<meta name='description' content='CodeIgniter User Guide' />
+
+</head>
+<body>
+
+<!-- START NAVIGATION -->
+<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div>
+<div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div>
+<div id="masthead">
+<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
+<tr>
+<td><h1>CodeIgniter User Guide Version 2.0.2</h1></td>
+<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
+</tr>
+</table>
+</div>
+<!-- END NAVIGATION -->
+
+
+<!-- START BREADCRUMB -->
+<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
+<tr>
+<td id="breadcrumb">
+<a href="http://codeigniter.com/">CodeIgniter Home</a> ›
+<a href="../index.html">User Guide Home</a> ›
+Encryption Class
+</td>
+<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td>
+</tr>
+</table>
+<!-- END BREADCRUMB -->
+
+<br clear="all" />
+
+
+<!-- START CONTENT -->
+<div id="content">
+
+
+<h1>Encryption Class</h1>
+
+<p>The Encryption Class provides two-way data encryption. It uses a scheme that either compiles
+the message using a randomly hashed bitwise XOR encoding scheme, or is encrypted using
+the Mcrypt library. If Mcrypt is not available on your server the encoded message will
+still provide a reasonable degree of security for encrypted sessions or other such "light" purposes.
+If Mcrypt is available, you'll be provided with a high degree of security appropriate for storage.</p>
+
+
+<h2>Setting your Key</h2>
+
+<p>A <em>key</em> is a piece of information that controls the cryptographic process and permits an encrypted string to be decoded.
+In fact, the key you chose will provide the <strong>only</strong> means to decode data that was encrypted with that key,
+so not only must you choose the key carefully, you must never change it if you intend use it for persistent data.</p>
+
+<p>It goes without saying that you should guard your key carefully.
+Should someone gain access to your key, the data will be easily decoded. If your server is not totally under your control
+it's impossible to ensure key security so you may want to think carefully before using it for anything
+that requires high security, like storing credit card numbers.</p>
+
+<p>To take maximum advantage of the encryption algorithm, your key should be 32 characters in length (128 bits).
+The key should be as random a string as you can concoct, with numbers and uppercase and lowercase letters.
+Your key should <strong>not</strong> be a simple text string. In order to be cryptographically secure it
+needs to be as random as possible.</p>
+
+<p>Your key can be either stored in your <dfn>application/config/config.php</dfn>, or you can design your own
+storage mechanism and pass the key dynamically when encoding/decoding.</p>
+
+<p>To save your key to your <dfn>application/config/config.php</dfn>, open the file and set:</p>
+<code>$config['encryption_key'] = "YOUR KEY";</code>
+
+
+<h2>Message Length</h2>
+
+<p>It's important for you to know that the encoded messages the encryption function generates will be approximately 2.6 times longer than the original
+message. For example, if you encrypt the string "my super secret data", which is 21 characters in length, you'll end up
+with an encoded string that is roughly 55 characters (we say "roughly" because the encoded string length increments in
+64 bit clusters, so it's not exactly linear). Keep this information in mind when selecting your data storage mechanism. Cookies,
+for example, can only hold 4K of information.</p>
+
+
+<h2>Initializing the Class</h2>
+
+<p>Like most other classes in CodeIgniter, the Encryption class is initialized in your controller using the <dfn>$this->load->library</dfn> function:</p>
+
+<code>$this->load->library('encrypt');</code>
+<p>Once loaded, the Encrypt library object will be available using: <dfn>$this->encrypt</dfn></p>
+
+
+<h2>$this->encrypt->encode()</h2>
+
+<p>Performs the data encryption and returns it as a string. Example:</p>
+<code>
+$msg = 'My secret message';<br />
+<br />
+$encrypted_string = $this->encrypt->encode($msg);</code>
+
+<p>You can optionally pass your encryption key via the second parameter if you don't want to use the one in your config file:</p>
+
+<code>
+$msg = 'My secret message';<br />
+$key = 'super-secret-key';<br />
+<br />
+$encrypted_string = $this->encrypt->encode($msg, $key);</code>
+
+
+<h2>$this->encrypt->decode()</h2>
+
+<p>Decrypts an encoded string. Example:</p>
+
+<code>
+$encrypted_string = 'APANtByIGI1BpVXZTJgcsAG8GZl8pdwwa84';<br />
+<br />
+$plaintext_string = $this->encrypt->decode($encrypted_string);</code>
+
+<p>You can optionally pass your encryption key via the second parameter if you don't want to use the one in your config file:</p>
+
+<code>
+$msg = 'My secret message';<br />
+$key = 'super-secret-key';<br />
+<br />
+$encrypted_string = $this->encrypt->decode($msg, $key);</code>
+
+
+<h2>$this->encrypt->set_cipher();</h2>
+
+<p>Permits you to set an Mcrypt cipher. By default it uses <samp>MCRYPT_RIJNDAEL_256</samp>. Example:</p>
+<code>$this->encrypt->set_cipher(MCRYPT_BLOWFISH);</code>
+<p>Please visit php.net for a list of <a href="http://php.net/mcrypt">available ciphers</a>.</p>
+
+<p>If you'd like to manually test whether your server supports Mcrypt you can use:</p>
+<code>echo ( ! function_exists('mcrypt_encrypt')) ? 'Nope' : 'Yup';</code>
+
+
+<h2>$this->encrypt->set_mode();</h2>
+
+<p>Permits you to set an Mcrypt mode. By default it uses <samp>MCRYPT_MODE_CBC</samp>. Example:</p>
+<code>$this->encrypt->set_mode(MCRYPT_MODE_CFB);</code>
+<p>Please visit php.net for a list of <a href="http://php.net/mcrypt">available modes</a>.</p>
+
+
+<h2>$this->encrypt->sha1();</h2>
+<p>SHA1 encoding function. Provide a string and it will return a 160 bit one way hash. Note: SHA1, just like MD5 is non-decodable. Example:</p>
+<code>$hash = $this->encrypt->sha1('Some string');</code>
+
+<p>Many PHP installations have SHA1 support by default so if all you need is to encode a hash it's simpler to use the native
+function:</p>
+
+<code>$hash = sha1('Some string');</code>
+
+<p>If your server does not support SHA1 you can use the provided function.</p>
+
+<h2 id="legacy">$this->encrypt->encode_from_legacy(<kbd>$orig_data</kbd>, <kbd>$legacy_mode</kbd> = MCRYPT_MODE_ECB, <kbd>$key</kbd> = '');</h2>
+<p>Enables you to re-encode data that was originally encrypted with CodeIgniter 1.x to be compatible with the Encryption library in CodeIgniter 2.x. It is only
+ necessary to use this method if you have encrypted data stored permanently such as in a file or database and are on a server that supports Mcrypt. "Light" use encryption
+ such as encrypted session data or transitory encrypted flashdata require no intervention on your part. However, existing encrypted Sessions will be
+ destroyed since data encrypted prior to 2.x will not be decoded.</p>
+
+<p class="important"><strong>Why only a method to re-encode the data instead of maintaining legacy methods for both encoding and decoding?</strong> The algorithms in
+ the Encryption library have improved in CodeIgniter 2.x both for performance and security, and we do not wish to encourage continued use of the older methods.
+ You can of course extend the Encryption library if you wish and replace the new methods with the old and retain seamless compatibility with CodeIgniter 1.x
+ encrypted data, but this a decision that a developer should make cautiously and deliberately, if at all.</p>
+
+<code>$new_data = $this->encrypt->encode_from_legacy(<kbd>$old_encrypted_string</kbd>);</code>
+
+<table cellpadding="0" cellspacing="1" border="0" style="width:100%" class="tableborder">
+<tr>
+ <th>Parameter</th>
+ <th>Default</th>
+ <th>Description</th>
+</tr>
+<tr>
+ <td class="td"><strong>$orig_data</strong></td>
+ <td class="td">n/a</td>
+ <td class="td">The original encrypted data from CodeIgniter 1.x's Encryption library</td>
+</tr>
+<tr>
+ <td class="td"><strong>$legacy_mode</strong></td>
+ <td class="td">MCRYPT_MODE_ECB</td>
+ <td class="td">The Mcrypt mode that was used to generate the original encrypted data. CodeIgniter 1.x's default was MCRYPT_MODE_ECB, and it will
+ assume that to be the case unless overridden by this parameter.</td>
+</tr>
+<tr>
+ <td class="td"><strong>$key</strong></td>
+ <td class="td">n/a</td>
+ <td class="td">The encryption key. This it typically specified in your config file as outlined above.</td>
+</tr>
+</table>
+
+</div>
+<!-- END CONTENT -->
+
+
+<div id="footer">
+<p>
+Previous Topic: <a href="email.html">Email Class</a>
+ ·
+<a href="#top">Top of Page</a> ·
+<a href="../index.html">User Guide Home</a> ·
+Next Topic: <a href="file_uploading.html">File Uploading Class</a>
+</p>
+<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2011 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
+</div>
+
+</body>
+</html>
\ No newline at end of file
projects / living-lab-site.git / blobdiff