summaryrefslogtreecommitdiffstats
path: root/user_guide
diff options
context:
space:
mode:
authorDerek Jones <derek.jones@ellislab.com>2010-08-31 20:17:10 +0200
committerDerek Jones <derek.jones@ellislab.com>2010-08-31 20:17:10 +0200
commit09c7793b23ae77c54e25d12b63d8ca9c9232efeb (patch)
tree887f1887200491e8846693932ea0cd39ebdd4864 /user_guide
parentb1e973247b66e0f4dc576484add50c2ebe10125a (diff)
Significant changes to the Encryption library
- Removed double-encoding with XOR scheme when Mcrypt is available. Additional obfuscation was not significantly aiding security, and came at a very high performance cost. - Changed the default encryption mode from ECB to CBC for much improved security - Added an encode_from_legacy() method to allow re-encoding of permanent data that was originally encoded with the older methods.
Diffstat (limited to 'user_guide')
-rw-r--r--user_guide/changelog.html4
-rw-r--r--user_guide/installation/upgrade_200.html15
-rw-r--r--user_guide/libraries/encryption.html44
3 files changed, 57 insertions, 6 deletions
diff --git a/user_guide/changelog.html b/user_guide/changelog.html
index d9c17ab76..c42bde01e 100644
--- a/user_guide/changelog.html
+++ b/user_guide/changelog.html
@@ -100,6 +100,10 @@ Hg Tag: </p>
<li>Added a second parameter (boolean) to <kbd>$this->zip->read_dir('/path/to/directory', FALSE)</kbd> to remove the preceding trail of empty folders when creating a Zip archive. This example would contain a zip with "directory" and all of its contents.</li>
<li>Added ability in the Image Library to handle PNG transparency for resize operations when using the GD lib.</li>
<li>Modified the Session class to prevent use if no encryption key is set in the config file.</li>
+ <li>Improved performance of the Encryption library on servers where Mcrypt is available.</li>
+ <li>Changed the default encryption mode in the Encryption library to CBC.</li>
+ <li>Added an <kbd>encode_from_legacy()</kbd> method to provide a way to transition encrypted data from CodeIgniter 1.x to CodeIgniter 2.x.
+ Please see the <a href="./installation/upgrade_200.html">upgrade instructions</a> for details.</li>
</ul>
</li>
<li>Database
diff --git a/user_guide/installation/upgrade_200.html b/user_guide/installation/upgrade_200.html
index f45875b3c..155df90d3 100644
--- a/user_guide/installation/upgrade_200.html
+++ b/user_guide/installation/upgrade_200.html
@@ -89,7 +89,20 @@ to
</p>
-<h2>Step 3: Update your user guide</h2>
+<h2>Step 4: Update stored encrypted data</h2>
+
+<p class="important"><strong>Note:</strong> If your application does not use the Encryption library, does not store Encrypted data permanently, or is on an environment that does not support Mcrypt, you may skip this step.</p>
+
+<p>The Encryption library has had a number of improvements, some for encryption strength and some for performance, that has an unavoidable consequence of
+ making it no longer possible to decode encrypted data produced by the original version of this library. To help with the transition, a new method has
+ been added, <kbd>encode_from_legacy()</kbd> that will decode the data with the original algorithm and return a re-encoded string using the improved methods.
+ This will enable you to easily replace stale encrypted data with fresh in your applications, either on the fly or en masse.</p>
+
+<p>Please read <a href="../libraries/encryption.html#legacy">how to use this method</a> in the Encryption library documentation.</p>
+
+</p>
+
+<h2>Step 5: Update your user guide</h2>
<p>Please replace your local copy of the user guide with the new version, including the image files.</p>
</div>
diff --git a/user_guide/libraries/encryption.html b/user_guide/libraries/encryption.html
index dac1db911..fbffd63c6 100644
--- a/user_guide/libraries/encryption.html
+++ b/user_guide/libraries/encryption.html
@@ -58,12 +58,11 @@ Encryption Class
<h1>Encryption Class</h1>
-<p>The Encryption Class provides two-way data encryption. It uses a scheme that pre-compiles
-the message using a randomly hashed bitwise XOR encoding scheme, which is then encrypted using
+<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 effectively end up with a double-encrypted message string, which should
-provide a very high degree of security.</p>
+If Mcrypt is available, you'll be provided with a high degree of security appropriate for storage.</p>
<h2>Setting your Key</h2>
@@ -153,7 +152,7 @@ $encrypted_string = $this->encrypt->decode($msg, $key);</code>
<h2>$this->encrypt->set_mode();</h2>
-<p>Permits you to set an Mcrypt mode. By default it uses <samp>MCRYPT_MODE_ECB</samp>. Example:</p>
+<p>Permits you to set an Mcrypt mode. By default it uses <samp>MCRYPT_MODE_CBC</samp>. Example:</p>
<code>$this->encrypt->set_mode(MCRYPT_MODE_CFB);</code>
<p>Please visit php.net for a list of <a href="http://php.net/mcrypt">available modes</a>.</p>
@@ -169,7 +168,42 @@ function:</p>
<p>If your server does not support SHA1 you can use the provided function.</p>
+<h2 id="legacy">$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 -->