You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
1406 lines
78 KiB
1406 lines
78 KiB
|
|
|
|
<!DOCTYPE html>
|
|
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
|
|
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
|
|
<head>
|
|
<meta charset="utf-8">
|
|
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
|
|
|
<title>Encryption Library — CodeIgniter 3.1.4 documentation</title>
|
|
|
|
|
|
|
|
|
|
<link rel="shortcut icon" href="../_static/ci-icon.ico"/>
|
|
|
|
|
|
|
|
<link href='https://fonts.googleapis.com/css?family=Lato:400,700,400italic,700italic|Roboto+Slab:400,700|Inconsolata:400,700&subset=latin,cyrillic' rel='stylesheet' type='text/css'>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<link rel="stylesheet" href="../_static/css/citheme.css" type="text/css" />
|
|
|
|
|
|
|
|
<link rel="top" title="CodeIgniter 3.1.4 documentation" href="../index.html"/>
|
|
<link rel="up" title="Libraries" href="index.html"/>
|
|
<link rel="next" title="File Uploading Class" href="file_uploading.html"/>
|
|
<link rel="prev" title="Encrypt Class" href="encrypt.html"/>
|
|
|
|
|
|
<script src="https://cdnjs.cloudflare.com/ajax/libs/modernizr/2.6.2/modernizr.min.js"></script>
|
|
|
|
</head>
|
|
|
|
<body class="wy-body-for-nav" role="document">
|
|
|
|
<div id="nav">
|
|
<div id="nav_inner">
|
|
|
|
|
|
|
|
<div id="pulldown-menu" class="ciNav">
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../general/welcome.html">Welcome to CodeIgniter</a><ul class="simple">
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation Instructions</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../installation/downloads.html">Downloading CodeIgniter</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../installation/index.html">Installation Instructions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../installation/upgrading.html">Upgrading From a Previous Version</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../installation/troubleshooting.html">Troubleshooting</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../overview/index.html">CodeIgniter Overview</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/getting_started.html">Getting Started</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/at_a_glance.html">CodeIgniter at a Glance</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/features.html">Supported Features</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/appflow.html">Application Flow Chart</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/mvc.html">Model-View-Controller</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/goals.html">Architectural Goals</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../tutorial/index.html">Tutorial</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../tutorial/static_pages.html">Static pages</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../tutorial/news_section.html">News section</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../tutorial/create_news_items.html">Create news items</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../tutorial/conclusion.html">Conclusion</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing to CodeIgniter</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../documentation/index.html">Writing CodeIgniter Documentation</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../DCO.html">Developer’s Certificate of Origin 1.1</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../general/index.html">General Topics</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/urls.html">CodeIgniter URLs</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/controllers.html">Controllers</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/reserved_names.html">Reserved Names</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/views.html">Views</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/models.html">Models</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/helpers.html">Helpers</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/libraries.html">Using CodeIgniter Libraries</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/creating_libraries.html">Creating Libraries</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/drivers.html">Using CodeIgniter Drivers</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/creating_drivers.html">Creating Drivers</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/core_classes.html">Creating Core System Classes</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/ancillary_classes.html">Creating Ancillary Classes</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/hooks.html">Hooks - Extending the Framework Core</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/autoloader.html">Auto-loading Resources</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/common_functions.html">Common Functions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/compatibility_functions.html">Compatibility Functions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/routing.html">URI Routing</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/errors.html">Error Handling</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/caching.html">Caching</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/profiling.html">Profiling Your Application</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/cli.html">Running via the CLI</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/managing_apps.html">Managing your Applications</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/environments.html">Handling Multiple Environments</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/alternative_php.html">Alternate PHP Syntax for View Files</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/security.html">Security</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/styleguide.html">PHP Style Guide</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul class="current">
|
|
<li class="toctree-l1 current"><a class="reference internal" href="index.html">Libraries</a><ul class="current">
|
|
<li class="toctree-l2"><a class="reference internal" href="benchmark.html">Benchmarking Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="caching.html">Caching Driver</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="calendar.html">Calendaring Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="cart.html">Shopping Cart Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="config.html">Config Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="email.html">Email Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="encrypt.html">Encrypt Class</a></li>
|
|
<li class="toctree-l2 current"><a class="current reference internal" href="">Encryption Library</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="file_uploading.html">File Uploading Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="form_validation.html">Form Validation</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="ftp.html">FTP Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="image_lib.html">Image Manipulation Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="input.html">Input Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="javascript.html">Javascript Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="language.html">Language Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="loader.html">Loader Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="migration.html">Migrations Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="output.html">Output Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="pagination.html">Pagination Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="parser.html">Template Parser Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="security.html">Security Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="sessions.html">Session Library</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="table.html">HTML Table Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="trackback.html">Trackback Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="typography.html">Typography Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="unit_testing.html">Unit Testing Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="uri.html">URI Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="user_agent.html">User Agent Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="xmlrpc.html">XML-RPC and XML-RPC Server Classes</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="zip.html">Zip Encoding Class</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../database/index.html">Database Reference</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/examples.html">Quick Start: Usage Examples</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/configuration.html">Database Configuration</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/connecting.html">Connecting to a Database</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/queries.html">Running Queries</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/results.html">Generating Query Results</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/helpers.html">Query Helper Functions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/query_builder.html">Query Builder Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/transactions.html">Transactions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/metadata.html">Getting MetaData</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/call_function.html">Custom Function Calls</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/caching.html">Query Caching</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/forge.html">Database Manipulation with Database Forge</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/utilities.html">Database Utilities Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/db_driver_reference.html">Database Driver Reference</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../helpers/index.html">Helpers</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/array_helper.html">Array Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/captcha_helper.html">CAPTCHA Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/cookie_helper.html">Cookie Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/date_helper.html">Date Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/directory_helper.html">Directory Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/download_helper.html">Download Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/email_helper.html">Email Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/file_helper.html">File Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/form_helper.html">Form Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/html_helper.html">HTML Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/inflector_helper.html">Inflector Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/language_helper.html">Language Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/number_helper.html">Number Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/path_helper.html">Path Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/security_helper.html">Security Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/smiley_helper.html">Smiley Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/string_helper.html">String Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/text_helper.html">Text Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/typography_helper.html">Typography Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/url_helper.html">URL Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/xml_helper.html">XML Helper</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
</div>
|
|
<div id="nav2">
|
|
<a href="#" id="openToc">
|
|
<img src="data:image/jpeg;base64,/9j/4AAQSkZJRgABAgAAZABkAAD/7AARRHVja3kAAQAEAAAARgAA/+4ADkFkb2JlAGTAAAAAAf/bAIQABAMDAwMDBAMDBAYEAwQGBwUEBAUHCAYGBwYGCAoICQkJCQgKCgwMDAwMCgwMDQ0MDBERERERFBQUFBQUFBQUFAEEBQUIBwgPCgoPFA4ODhQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQU/8AAEQgAKwCaAwERAAIRAQMRAf/EAHsAAQAABwEBAAAAAAAAAAAAAAABAwQFBgcIAgkBAQAAAAAAAAAAAAAAAAAAAAAQAAEDAwICBwYEAgsAAAAAAAIBAwQAEQUSBiEHkROTVNQWGDFBUVIUCHEiMtOUFWGBobHRQlMkZIRVEQEAAAAAAAAAAAAAAAAAAAAA/9oADAMBAAIRAxEAPwDSC+ygkOOaUoKigUCgUCgUCgUCgUCgUCgUCgkuGguIP9FBMFb0Hqg7We+3jlmIqqYFf4ub+/QYlnOR/LqIBKGFUbf8qWv971BytQXXE7Y3Lnm3HsFhp2TaZJAdchRXpIgSpdEJWxJEW3xoKV7F5OMy7JkQn2o7D6w33XGjEAkoiqrJEqIiOIiKuhePCgqp22dyYyS3CyWHnQ5joG61HkRnmnTbaFSMhExRVQRRVJU9iUHjE7ez+fJ0MFipmUNhBV8YUd2SoIV9KkjQla9ltegttBdPLW4/qocL+UTfrMiHW4+P9M71shuyrqaHTcxsl7jegpsji8nh5ZwMvDfgTm0RTjSmjYdFCS6KoOIipdFunCgmNYTMv457MMY6U7iI6oMieDDhRm1VbIhuoOkbqtuK0Hpzb+eZcYZexUxt6UyUqK2cd0SdjtgrhOgijcgERUlJOCIl6CpgbP3blRI8XgMjNARAyKNDfeRBdFDBVUAXgQrqH4pxoJTu2NysY97LP4ac1io5q1InHFeGO24LnVKJuKOkSQ/yKir+rh7aCLG1dzypZQI2FnvTgccYOM3FeN0XWERXAUEFVQgQkUktdLpegm+Td3/Xli/L+S/mYNJIOF9G/wBeLKrZHFb0akG6W1WtQWSg3Dyg5e7V3fipE3O4/wCrktyzYA+ufas2LbZIlmnAT2kvuoN1wft95augilglX/tzP3qCu9O3LL/wV/i5v79BvmTADq14UGu91467Z6U9y0HzH/ncj/U/sT/CgynZG7I2NezpZGUjIycJkYkZSG+uQ81pbBNKLxJfjwoMqZ3/ALYHl35AJ7/cuwHcu5k7r1Q5pHetBjquqVVJWGxj9Zrtcl/Ggy3dHMvauR3HFZj5nHNxSyW5JISYDMoIwx8tFIGHZhPNaykGapr6rUAiicEoMG21lMRj8buPAz8xhJrr7uOeiPTCyAwXUaGR1mgozbTusOsFLEiJ7fbQa/h7gcjy2H3V6xppwDNtUSxCJIqp7valBuWVzJ22xuCROXNNZiJkMtms0DbjUkAZjzoDrTMd9dDRI44ZC2YsrYdKWP2WDT2S3N9dNdlRYrGMYc06IURXSYb0igrpWS485xVNS6nF4rwslkoMwnbpgZLB7bmt5uMweAhDEl4B5uSLzzqTnnyVpW2jaJHRMSIjdDiiotvy3DOE5rYTEbkl5yFn28k7JyG4c7AU2HtLH1uKfaiMPI40CdYbpNtmLdwTSn5rewLNld+7TLdeal4WarWBkbVKBjgdElMJJwAAY5fl4kB3b1fp4XvagsGS3FjJfLzDNtS8aeXx7LzT7TyzByQE5PccRGRC0ZRUDRV6y62vbjagzLmJzS2vuPK43JY6aP1TW6Jz+RIWyFtyC06y3EkiiinAo7YCqfq1AqqnGgsOH3lhZO8d1pmcpB8j5XIm9OYlBJSQ/FSS4427DKO0RC8AlcEMhFdViRR1WDWR5t3WXVuL1d106kG9vdeye2g60+1FDyW0shIcXVpyroXt8I8dfd+NB1vioAdWnD3UF1+gD4UFc6CEKpagxXN43rwJLUHz7yX2c8zokt9uHlsPIhA4aRnnHJTLptIS6CNsY7iASpxUUMkReGpfbQW0vtN5pitvrsN28rwtBD0nc0+/Yft5XhaB6TuaXfsP28rwtA9J3NPv2H7eV4Wgek7mn37D9vK8LQPSdzT79h+3leFoHpO5pd+w/byvC0D0nc0u/Yft5XhaB6TuaXfsP28rwtA9J3NLv2H7eV4Wgek7ml37D9vK8LQPSdzS79h+3leFoHpO5p9+w/byvC0E9r7Reazy2HIYVPxkS/CUHVn26cosxyv2g7h89LYmZSXOenvLEQ1YaQ222RATcQCP8rSGqqA8S02W2pQ6FhMoAIlqCtsnwoCpdKClejI4i3Sgtb+GBxVuNBSFt1pV/RQefLjPyUDy4z8lA8uM/JQPLjPyUDy4z8lA8uM/JQPLjPyUDy4z8lA8uM/JQPLjPyUDy4z8lA8utJ/koJ7WCbBU/LQXOPAFq1koK8B0pag90CggtBBf6qB0UDooHRQOigdFA6KB0UDooHRQOigdFA6KB0UDooI0EaBQf//Z" title="Toggle Table of Contents" alt="Toggle Table of Contents" />
|
|
</a>
|
|
</div>
|
|
|
|
<div class="wy-grid-for-nav">
|
|
|
|
|
|
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
|
|
<div class="wy-side-nav-search">
|
|
|
|
<a href="../index.html" class="fa fa-home"> CodeIgniter</a>
|
|
|
|
|
|
<div role="search">
|
|
<form id="rtd-search-form" class="wy-form" action="../search.html" method="get">
|
|
<input type="text" name="q" placeholder="Search docs" />
|
|
<input type="hidden" name="check_keywords" value="yes" />
|
|
<input type="hidden" name="area" value="default" />
|
|
</form>
|
|
</div>
|
|
</div>
|
|
|
|
<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
|
|
|
|
|
|
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../general/welcome.html">Welcome to CodeIgniter</a><ul class="simple">
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation Instructions</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../installation/downloads.html">Downloading CodeIgniter</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../installation/index.html">Installation Instructions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../installation/upgrading.html">Upgrading From a Previous Version</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../installation/troubleshooting.html">Troubleshooting</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../overview/index.html">CodeIgniter Overview</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/getting_started.html">Getting Started</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/at_a_glance.html">CodeIgniter at a Glance</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/features.html">Supported Features</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/appflow.html">Application Flow Chart</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/mvc.html">Model-View-Controller</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../overview/goals.html">Architectural Goals</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../tutorial/index.html">Tutorial</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../tutorial/static_pages.html">Static pages</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../tutorial/news_section.html">News section</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../tutorial/create_news_items.html">Create news items</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../tutorial/conclusion.html">Conclusion</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing to CodeIgniter</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../documentation/index.html">Writing CodeIgniter Documentation</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../DCO.html">Developer’s Certificate of Origin 1.1</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../general/index.html">General Topics</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/urls.html">CodeIgniter URLs</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/controllers.html">Controllers</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/reserved_names.html">Reserved Names</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/views.html">Views</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/models.html">Models</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/helpers.html">Helpers</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/libraries.html">Using CodeIgniter Libraries</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/creating_libraries.html">Creating Libraries</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/drivers.html">Using CodeIgniter Drivers</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/creating_drivers.html">Creating Drivers</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/core_classes.html">Creating Core System Classes</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/ancillary_classes.html">Creating Ancillary Classes</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/hooks.html">Hooks - Extending the Framework Core</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/autoloader.html">Auto-loading Resources</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/common_functions.html">Common Functions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/compatibility_functions.html">Compatibility Functions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/routing.html">URI Routing</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/errors.html">Error Handling</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/caching.html">Caching</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/profiling.html">Profiling Your Application</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/cli.html">Running via the CLI</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/managing_apps.html">Managing your Applications</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/environments.html">Handling Multiple Environments</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/alternative_php.html">Alternate PHP Syntax for View Files</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/security.html">Security</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../general/styleguide.html">PHP Style Guide</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul class="current">
|
|
<li class="toctree-l1 current"><a class="reference internal" href="index.html">Libraries</a><ul class="current">
|
|
<li class="toctree-l2"><a class="reference internal" href="benchmark.html">Benchmarking Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="caching.html">Caching Driver</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="calendar.html">Calendaring Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="cart.html">Shopping Cart Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="config.html">Config Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="email.html">Email Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="encrypt.html">Encrypt Class</a></li>
|
|
<li class="toctree-l2 current"><a class="current reference internal" href="">Encryption Library</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="file_uploading.html">File Uploading Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="form_validation.html">Form Validation</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="ftp.html">FTP Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="image_lib.html">Image Manipulation Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="input.html">Input Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="javascript.html">Javascript Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="language.html">Language Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="loader.html">Loader Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="migration.html">Migrations Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="output.html">Output Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="pagination.html">Pagination Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="parser.html">Template Parser Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="security.html">Security Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="sessions.html">Session Library</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="table.html">HTML Table Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="trackback.html">Trackback Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="typography.html">Typography Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="unit_testing.html">Unit Testing Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="uri.html">URI Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="user_agent.html">User Agent Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="xmlrpc.html">XML-RPC and XML-RPC Server Classes</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="zip.html">Zip Encoding Class</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../database/index.html">Database Reference</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/examples.html">Quick Start: Usage Examples</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/configuration.html">Database Configuration</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/connecting.html">Connecting to a Database</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/queries.html">Running Queries</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/results.html">Generating Query Results</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/helpers.html">Query Helper Functions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/query_builder.html">Query Builder Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/transactions.html">Transactions</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/metadata.html">Getting MetaData</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/call_function.html">Custom Function Calls</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/caching.html">Query Caching</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/forge.html">Database Manipulation with Database Forge</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/utilities.html">Database Utilities Class</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../database/db_driver_reference.html">Database Driver Reference</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
<ul>
|
|
<li class="toctree-l1"><a class="reference internal" href="../helpers/index.html">Helpers</a><ul>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/array_helper.html">Array Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/captcha_helper.html">CAPTCHA Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/cookie_helper.html">Cookie Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/date_helper.html">Date Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/directory_helper.html">Directory Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/download_helper.html">Download Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/email_helper.html">Email Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/file_helper.html">File Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/form_helper.html">Form Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/html_helper.html">HTML Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/inflector_helper.html">Inflector Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/language_helper.html">Language Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/number_helper.html">Number Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/path_helper.html">Path Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/security_helper.html">Security Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/smiley_helper.html">Smiley Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/string_helper.html">String Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/text_helper.html">Text Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/typography_helper.html">Typography Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/url_helper.html">URL Helper</a></li>
|
|
<li class="toctree-l2"><a class="reference internal" href="../helpers/xml_helper.html">XML Helper</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
|
|
|
|
|
|
</div>
|
|
|
|
</nav>
|
|
|
|
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
|
|
|
|
|
|
<nav class="wy-nav-top" role="navigation" aria-label="top navigation">
|
|
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
|
|
<a href="../index.html">CodeIgniter</a>
|
|
</nav>
|
|
|
|
|
|
|
|
<div class="wy-nav-content">
|
|
<div class="rst-content">
|
|
<div role="navigation" aria-label="breadcrumbs navigation">
|
|
<ul class="wy-breadcrumbs">
|
|
<li><a href="../index.html">Docs</a> »</li>
|
|
|
|
<li><a href="index.html">Libraries</a> »</li>
|
|
|
|
<li>Encryption Library</li>
|
|
<li class="wy-breadcrumbs-aside">
|
|
|
|
</li>
|
|
<div style="float:right;margin-left:5px;" id="closeMe">
|
|
<img title="Classic Layout" alt="classic layout" src="data:image/gif;base64,R0lGODlhFAAUAJEAAAAAADMzM////wAAACH5BAUUAAIALAAAAAAUABQAAAImlI+py+0PU5gRBRDM3DxbWoXis42X13USOLauUIqnlsaH/eY6UwAAOw==" />
|
|
</div>
|
|
</ul>
|
|
<hr/>
|
|
</div>
|
|
<div role="main" class="document">
|
|
|
|
<div class="section" id="encryption-library">
|
|
<h1>Encryption Library<a class="headerlink" href="#encryption-library" title="Permalink to this headline">¶</a></h1>
|
|
<div class="admonition important">
|
|
<p class="first admonition-title">Important</p>
|
|
<p class="last">DO NOT use this or any other <em>encryption</em> library for
|
|
user password storage! Passwords must be <em>hashed</em> instead, and you
|
|
should do that via PHP’s own <a class="reference external" href="http://php.net/password">Password Hashing extension</a>.</p>
|
|
</div>
|
|
<p>The Encryption Library provides two-way data encryption. To do so in
|
|
a cryptographically secure way, it utilizes PHP extensions that are
|
|
unfortunately not always available on all systems.
|
|
You must meet one of the following dependencies in order to use this
|
|
library:</p>
|
|
<ul class="simple">
|
|
<li><a class="reference external" href="http://php.net/openssl">OpenSSL</a></li>
|
|
<li><a class="reference external" href="http://php.net/mcrypt">MCrypt</a> (and <cite>MCRYPT_DEV_URANDOM</cite> availability)</li>
|
|
</ul>
|
|
<p>If neither of the above dependencies is met, we simply cannot offer
|
|
you a good enough implementation to meet the high standards required
|
|
for proper cryptography.</p>
|
|
<div class="contents local topic" id="contents">
|
|
<ul class="simple">
|
|
<li><a class="reference internal" href="#using-the-encryption-library" id="id2">Using the Encryption Library</a><ul>
|
|
<li><a class="reference internal" href="#initializing-the-class" id="id3">Initializing the Class</a></li>
|
|
<li><a class="reference internal" href="#default-behavior" id="id4">Default behavior</a></li>
|
|
<li><a class="reference internal" href="#setting-your-encryption-key" id="id5">Setting your encryption_key</a></li>
|
|
<li><a class="reference internal" href="#supported-encryption-ciphers-and-modes" id="id6">Supported encryption ciphers and modes</a><ul>
|
|
<li><a class="reference internal" href="#portable-ciphers" id="id7">Portable ciphers</a></li>
|
|
<li><a class="reference internal" href="#driver-specific-ciphers" id="id8">Driver-specific ciphers</a></li>
|
|
<li><a class="reference internal" href="#encryption-modes" id="id9">Encryption modes</a></li>
|
|
</ul>
|
|
</li>
|
|
<li><a class="reference internal" href="#message-length" id="id10">Message Length</a></li>
|
|
<li><a class="reference internal" href="#configuring-the-library" id="id11">Configuring the library</a></li>
|
|
<li><a class="reference internal" href="#encrypting-and-decrypting-data" id="id12">Encrypting and decrypting data</a><ul>
|
|
<li><a class="reference internal" href="#how-it-works" id="id13">How it works</a></li>
|
|
<li><a class="reference internal" href="#using-custom-parameters" id="id14">Using custom parameters</a></li>
|
|
<li><a class="reference internal" href="#supported-hmac-authentication-algorithms" id="id15">Supported HMAC authentication algorithms</a></li>
|
|
</ul>
|
|
</li>
|
|
</ul>
|
|
</li>
|
|
<li><a class="reference internal" href="#class-reference" id="id16">Class Reference</a></li>
|
|
</ul>
|
|
</div>
|
|
<div class="custom-index container"></div><div class="section" id="using-the-encryption-library">
|
|
<h2><a class="toc-backref" href="#id2">Using the Encryption Library</a><a class="headerlink" href="#using-the-encryption-library" title="Permalink to this headline">¶</a></h2>
|
|
<div class="section" id="initializing-the-class">
|
|
<h3><a class="toc-backref" href="#id3">Initializing the Class</a><a class="headerlink" href="#initializing-the-class" title="Permalink to this headline">¶</a></h3>
|
|
<p>Like most other classes in CodeIgniter, the Encryption library is
|
|
initialized in your controller using the <tt class="docutils literal"><span class="pre">$this->load->library()</span></tt>
|
|
method:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">load</span><span class="o">-></span><span class="na">library</span><span class="p">(</span><span class="s1">'encryption'</span><span class="p">);</span>
|
|
</pre></div>
|
|
</div>
|
|
<p>Once loaded, the Encryption library object will be available using:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span>
|
|
</pre></div>
|
|
</div>
|
|
</div>
|
|
<div class="section" id="default-behavior">
|
|
<h3><a class="toc-backref" href="#id4">Default behavior</a><a class="headerlink" href="#default-behavior" title="Permalink to this headline">¶</a></h3>
|
|
<p>By default, the Encryption Library will use the AES-128 cipher in CBC
|
|
mode, using your configured <em>encryption_key</em> and SHA512 HMAC authentication.</p>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">AES-128 is chosen both because it is proven to be strong and
|
|
because of its wide availability across different cryptographic
|
|
software and programming languages’ APIs.</p>
|
|
</div>
|
|
<p>However, the <em>encryption_key</em> is not used as is.</p>
|
|
<p>If you are somewhat familiar with cryptography, you should already know
|
|
that a HMAC also requires a secret key and using the same key for both
|
|
encryption and authentication is a bad practice.</p>
|
|
<p>Because of that, two separate keys are derived from your already configured
|
|
<em>encryption_key</em>: one for encryption and one for authentication. This is
|
|
done via a technique called <a class="reference external" href="http://en.wikipedia.org/wiki/HKDF">HMAC-based Key Derivation Function</a> (HKDF).</p>
|
|
</div>
|
|
<div class="section" id="setting-your-encryption-key">
|
|
<h3><a class="toc-backref" href="#id5">Setting your encryption_key</a><a class="headerlink" href="#setting-your-encryption-key" title="Permalink to this headline">¶</a></h3>
|
|
<p>An <em>encryption key</em> is a piece of information that controls the
|
|
cryptographic process and permits a plain-text string to be encrypted,
|
|
and afterwards - decrypted. It is the secret “ingredient” in the whole
|
|
process that allows you to be the only one who is able to decrypt data
|
|
that you’ve decided to hide from the eyes of the public.
|
|
After one key is used to encrypt data, that same key provides the <strong>only</strong>
|
|
means to decrypt it, so not only must you chose one carefully, but you
|
|
must not lose it or you will also lose access to the data.</p>
|
|
<p>It must be noted that to ensure maximum security, such key <em>should</em> not
|
|
only be as strong as possible, but also often changed. Such behavior
|
|
however is rarely practical or possible to implement, and that is why
|
|
CodeIgniter gives you the ability to configure a single key that is to be
|
|
used (almost) every time.</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 decrypted. 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>Your encryption key <strong>must</strong> be as long as the encyption algorithm in use
|
|
allows. For AES-128, that’s 128 bits or 16 bytes (charcters) long.
|
|
You will find a table below that shows the supported key lengths of
|
|
different ciphers.</p>
|
|
<p>The key should be as random as possible and it <strong>must not</strong> be a regular
|
|
text string, nor the output of a hashing function, etc. In order to create
|
|
a proper key, you must use the Encryption library’s <tt class="docutils literal"><span class="pre">create_key()</span></tt> method</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="c1">// $key will be assigned a 16-byte (128-bit) random key</span>
|
|
<span class="nv">$key</span> <span class="o">=</span> <span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">create_key</span><span class="p">(</span><span class="mi">16</span><span class="p">);</span>
|
|
</pre></div>
|
|
</div>
|
|
<p>The key can be either stored in your <em>application/config/config.php</em>, or
|
|
you can design your own storage mechanism and pass the key dynamically
|
|
when encrypting/decrypting.</p>
|
|
<p>To save your key to your <em>application/config/config.php</em>, open the file
|
|
and set:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$config</span><span class="p">[</span><span class="s1">'encryption_key'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'YOUR KEY'</span><span class="p">;</span>
|
|
</pre></div>
|
|
</div>
|
|
<p>You’ll notice that the <tt class="docutils literal"><span class="pre">create_key()</span></tt> method outputs binary data, which
|
|
is hard to deal with (i.e. a copy-paste may damage it), so you may use
|
|
<tt class="docutils literal"><span class="pre">bin2hex()</span></tt>, <tt class="docutils literal"><span class="pre">hex2bin()</span></tt> or Base64-encoding to work with the key in
|
|
a more friendly manner. For example:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="c1">// Get a hex-encoded representation of the key:</span>
|
|
<span class="nv">$key</span> <span class="o">=</span> <span class="nb">bin2hex</span><span class="p">(</span><span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">create_key</span><span class="p">(</span><span class="mi">16</span><span class="p">));</span>
|
|
|
|
<span class="c1">// Put the same value in your config with hex2bin(),</span>
|
|
<span class="c1">// so that it is still passed as binary to the library:</span>
|
|
<span class="nv">$config</span><span class="p">[</span><span class="s1">'encryption_key'</span><span class="p">]</span> <span class="o">=</span> <span class="nb">hex2bin</span><span class="p">(</span><span class="o"><</span><span class="nx">your</span> <span class="nx">hex</span><span class="o">-</span><span class="nx">encoded</span> <span class="nb">key</span><span class="o">></span><span class="p">);</span>
|
|
</pre></div>
|
|
</div>
|
|
</div>
|
|
<div class="section" id="supported-encryption-ciphers-and-modes">
|
|
<span id="ciphers-and-modes"></span><h3><a class="toc-backref" href="#id6">Supported encryption ciphers and modes</a><a class="headerlink" href="#supported-encryption-ciphers-and-modes" title="Permalink to this headline">¶</a></h3>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">The terms ‘cipher’ and ‘encryption algorithm’ are interchangeable.</p>
|
|
</div>
|
|
<div class="section" id="portable-ciphers">
|
|
<h4><a class="toc-backref" href="#id7">Portable ciphers</a><a class="headerlink" href="#portable-ciphers" title="Permalink to this headline">¶</a></h4>
|
|
<p>Because MCrypt and OpenSSL (also called drivers throughout this document)
|
|
each support different sets of encryption algorithms and often implement
|
|
them in different ways, our Encryption library is designed to use them in
|
|
a portable fashion, or in other words - it enables you to use them
|
|
interchangeably, at least for the ciphers supported by both drivers.</p>
|
|
<p>It is also implemented in a way that aims to match the standard
|
|
implementations in other programming languages and libraries.</p>
|
|
<p>Here’s a list of the so called “portable” ciphers, where
|
|
“CodeIgniter name” is the string value that you’d have to pass to the
|
|
Encryption library to use that cipher:</p>
|
|
<table border="1" class="docutils">
|
|
<colgroup>
|
|
<col width="24%" />
|
|
<col width="18%" />
|
|
<col width="28%" />
|
|
<col width="31%" />
|
|
</colgroup>
|
|
<thead valign="bottom">
|
|
<tr class="row-odd"><th class="head">Cipher name</th>
|
|
<th class="head">CodeIgniter name</th>
|
|
<th class="head">Key lengths (bits / bytes)</th>
|
|
<th class="head">Supported modes</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody valign="top">
|
|
<tr class="row-even"><td>AES-128 / Rijndael-128</td>
|
|
<td>aes-128</td>
|
|
<td>128 / 16</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>AES-192</td>
|
|
<td>aes-192</td>
|
|
<td>192 / 24</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>AES-256</td>
|
|
<td>aes-256</td>
|
|
<td>256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>DES</td>
|
|
<td>des</td>
|
|
<td>56 / 7</td>
|
|
<td>CBC, CFB, CFB8, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>TripleDES</td>
|
|
<td>tripledes</td>
|
|
<td>56 / 7, 112 / 14, 168 / 21</td>
|
|
<td>CBC, CFB, CFB8, OFB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>Blowfish</td>
|
|
<td>blowfish</td>
|
|
<td>128-448 / 16-56</td>
|
|
<td>CBC, CFB, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>CAST5 / CAST-128</td>
|
|
<td>cast5</td>
|
|
<td>88-128 / 11-16</td>
|
|
<td>CBC, CFB, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>RC4 / ARCFour</td>
|
|
<td>rc4</td>
|
|
<td>40-2048 / 5-256</td>
|
|
<td>Stream</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<div class="admonition important">
|
|
<p class="first admonition-title">Important</p>
|
|
<p class="last">Because of how MCrypt works, if you fail to provide a key
|
|
with the appropriate length, you might end up using a different
|
|
algorithm than the one configured, so be really careful with that!</p>
|
|
</div>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">In case it isn’t clear from the above table, Blowfish, CAST5
|
|
and RC4 support variable length keys. That is, any number in the
|
|
shown ranges is valid, although in bit terms that only happens
|
|
in 8-bit increments.</p>
|
|
</div>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">Even though CAST5 supports key lengths lower than 128 bits
|
|
(16 bytes), in fact they will just be zero-padded to the
|
|
maximum length, as specified in <a class="reference external" href="http://tools.ietf.org/rfc/rfc2144.txt">RFC 2144</a>.</p>
|
|
</div>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">Blowfish supports key lengths as small as 32 bits (4 bytes), but
|
|
our tests have shown that only lengths of 128 bits (16 bytes) or
|
|
higher are properly supported by both MCrypt and OpenSSL. It is
|
|
also a bad practice to use such low-length keys anyway.</p>
|
|
</div>
|
|
</div>
|
|
<div class="section" id="driver-specific-ciphers">
|
|
<h4><a class="toc-backref" href="#id8">Driver-specific ciphers</a><a class="headerlink" href="#driver-specific-ciphers" title="Permalink to this headline">¶</a></h4>
|
|
<p>As noted above, MCrypt and OpenSSL support different sets of encryption
|
|
ciphers. For portability reasons and because we haven’t tested them
|
|
properly, we do not advise you to use the ones that are driver-specific,
|
|
but regardless, here’s a list of most of them:</p>
|
|
<table border="1" class="docutils">
|
|
<colgroup>
|
|
<col width="15%" />
|
|
<col width="10%" />
|
|
<col width="32%" />
|
|
<col width="44%" />
|
|
</colgroup>
|
|
<thead valign="bottom">
|
|
<tr class="row-odd"><th class="head">Cipher name</th>
|
|
<th class="head">Driver</th>
|
|
<th class="head">Key lengths (bits / bytes)</th>
|
|
<th class="head">Supported modes</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody valign="top">
|
|
<tr class="row-even"><td>AES-128</td>
|
|
<td>OpenSSL</td>
|
|
<td>128 / 16</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, ECB, XTS</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>AES-192</td>
|
|
<td>OpenSSL</td>
|
|
<td>192 / 24</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, ECB, XTS</td>
|
|
</tr>
|
|
<tr class="row-even"><td>AES-256</td>
|
|
<td>OpenSSL</td>
|
|
<td>256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, ECB, XTS</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>Rijndael-128</td>
|
|
<td>MCrypt</td>
|
|
<td>128 / 16, 192 / 24, 256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>Rijndael-192</td>
|
|
<td>MCrypt</td>
|
|
<td>128 / 16, 192 / 24, 256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>Rijndael-256</td>
|
|
<td>MCrypt</td>
|
|
<td>128 / 16, 192 / 24, 256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>GOST</td>
|
|
<td>MCrypt</td>
|
|
<td>256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>Twofish</td>
|
|
<td>MCrypt</td>
|
|
<td>128 / 16, 192 / 24, 256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>CAST-128</td>
|
|
<td>MCrypt</td>
|
|
<td>40-128 / 5-16</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>CAST-256</td>
|
|
<td>MCrypt</td>
|
|
<td>128 / 16, 192 / 24, 256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>Loki97</td>
|
|
<td>MCrypt</td>
|
|
<td>128 / 16, 192 / 24, 256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>SaferPlus</td>
|
|
<td>MCrypt</td>
|
|
<td>128 / 16, 192 / 24, 256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>Serpent</td>
|
|
<td>MCrypt</td>
|
|
<td>128 / 16, 192 / 24, 256 / 32</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>XTEA</td>
|
|
<td>MCrypt</td>
|
|
<td>128 / 16</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>RC2</td>
|
|
<td>MCrypt</td>
|
|
<td>8-1024 / 1-128</td>
|
|
<td>CBC, CTR, CFB, CFB8, OFB, OFB8, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>RC2</td>
|
|
<td>OpenSSL</td>
|
|
<td>8-1024 / 1-128</td>
|
|
<td>CBC, CFB, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>Camellia-128</td>
|
|
<td>OpenSSL</td>
|
|
<td>128 / 16</td>
|
|
<td>CBC, CFB, CFB8, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>Camellia-192</td>
|
|
<td>OpenSSL</td>
|
|
<td>192 / 24</td>
|
|
<td>CBC, CFB, CFB8, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-even"><td>Camellia-256</td>
|
|
<td>OpenSSL</td>
|
|
<td>256 / 32</td>
|
|
<td>CBC, CFB, CFB8, OFB, ECB</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>Seed</td>
|
|
<td>OpenSSL</td>
|
|
<td>128 / 16</td>
|
|
<td>CBC, CFB, OFB, ECB</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">If you wish to use one of those ciphers, you’d have to pass
|
|
its name in lower-case to the Encryption library.</p>
|
|
</div>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">You’ve probably noticed that all AES cipers (and Rijndael-128)
|
|
are also listed in the portable ciphers list. This is because
|
|
drivers support different modes for these ciphers. Also, it is
|
|
important to note that AES-128 and Rijndael-128 are actually
|
|
the same cipher, but <strong>only</strong> when used with a 128-bit key.</p>
|
|
</div>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">CAST-128 / CAST-5 is also listed in both the portable and
|
|
driver-specific ciphers list. This is because OpenSSL’s
|
|
implementation doesn’t appear to be working correctly with
|
|
key sizes of 80 bits and lower.</p>
|
|
</div>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">RC2 is listed as supported by both MCrypt and OpenSSL.
|
|
However, both drivers implement them differently and they
|
|
are not portable. It is probably worth noting that we only
|
|
found one obscure source confirming that it is MCrypt that
|
|
is not properly implementing it.</p>
|
|
</div>
|
|
</div>
|
|
<div class="section" id="encryption-modes">
|
|
<span id="id1"></span><h4><a class="toc-backref" href="#id9">Encryption modes</a><a class="headerlink" href="#encryption-modes" title="Permalink to this headline">¶</a></h4>
|
|
<p>Different modes of encryption have different characteristics and serve
|
|
for different purposes. Some are stronger than others, some are faster
|
|
and some offer extra features.
|
|
We are not going in depth into that here, we’ll leave that to the
|
|
cryptography experts. The table below is to provide brief informational
|
|
reference to our more experienced users. If you are a beginner, just
|
|
stick to the CBC mode - it is widely accepted as strong and secure for
|
|
general purposes.</p>
|
|
<table border="1" class="docutils">
|
|
<colgroup>
|
|
<col width="6%" />
|
|
<col width="9%" />
|
|
<col width="9%" />
|
|
<col width="76%" />
|
|
</colgroup>
|
|
<thead valign="bottom">
|
|
<tr class="row-odd"><th class="head">Mode name</th>
|
|
<th class="head">CodeIgniter name</th>
|
|
<th class="head">Driver support</th>
|
|
<th class="head">Additional info</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody valign="top">
|
|
<tr class="row-even"><td>CBC</td>
|
|
<td>cbc</td>
|
|
<td>MCrypt, OpenSSL</td>
|
|
<td>A safe default choice</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>CTR</td>
|
|
<td>ctr</td>
|
|
<td>MCrypt, OpenSSL</td>
|
|
<td>Considered as theoretically better than CBC, but not as widely available</td>
|
|
</tr>
|
|
<tr class="row-even"><td>CFB</td>
|
|
<td>cfb</td>
|
|
<td>MCrypt, OpenSSL</td>
|
|
<td>N/A</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>CFB8</td>
|
|
<td>cfb8</td>
|
|
<td>MCrypt, OpenSSL</td>
|
|
<td>Same as CFB, but operates in 8-bit mode (not recommended).</td>
|
|
</tr>
|
|
<tr class="row-even"><td>OFB</td>
|
|
<td>ofb</td>
|
|
<td>MCrypt, OpenSSL</td>
|
|
<td>N/A</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>OFB8</td>
|
|
<td>ofb8</td>
|
|
<td>MCrypt</td>
|
|
<td>Same as OFB, but operates in 8-bit mode (not recommended).</td>
|
|
</tr>
|
|
<tr class="row-even"><td>ECB</td>
|
|
<td>ecb</td>
|
|
<td>MCrypt, OpenSSL</td>
|
|
<td>Ignores IV (not recommended).</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>XTS</td>
|
|
<td>xts</td>
|
|
<td>OpenSSL</td>
|
|
<td>Usually used for encrypting random access data such as RAM or hard-disk storage.</td>
|
|
</tr>
|
|
<tr class="row-even"><td>Stream</td>
|
|
<td>stream</td>
|
|
<td>MCrypt, OpenSSL</td>
|
|
<td>This is not actually a mode, it just says that a stream cipher is being used. Required because of the general cipher+mode initialization process.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
</div>
|
|
</div>
|
|
<div class="section" id="message-length">
|
|
<h3><a class="toc-backref" href="#id10">Message Length</a><a class="headerlink" href="#message-length" title="Permalink to this headline">¶</a></h3>
|
|
<p>It’s probably important for you to know that an encrypted string is usually
|
|
longer than the original, plain-text string (depending on the cipher).</p>
|
|
<p>This is influenced by the cipher algorithm itself, the IV prepended to the
|
|
cipher-text and the HMAC authentication message that is also prepended.
|
|
Furthermore, the encrypted message is also Base64-encoded so that it is safe
|
|
for storage and transmission, regardless of a possible character set in use.</p>
|
|
<p>Keep this information in mind when selecting your data storage mechanism.
|
|
Cookies, for example, can only hold 4K of information.</p>
|
|
</div>
|
|
<div class="section" id="configuring-the-library">
|
|
<span id="configuration"></span><h3><a class="toc-backref" href="#id11">Configuring the library</a><a class="headerlink" href="#configuring-the-library" title="Permalink to this headline">¶</a></h3>
|
|
<p>For usability, performance, but also historical reasons tied to our old
|
|
<a class="reference internal" href="encrypt.html"><em>Encrypt Class</em></a>, the Encryption library is designed to
|
|
use repeatedly the same driver, encryption cipher, mode and key.</p>
|
|
<p>As noted in the “Default behavior” section above, this means using an
|
|
auto-detected driver (OpenSSL has a higher priority), the AES-128 ciper
|
|
in CBC mode, and your <tt class="docutils literal"><span class="pre">$config['encryption_key']</span></tt> value.</p>
|
|
<p>If you wish to change that however, you need to use the <tt class="docutils literal"><span class="pre">initialize()</span></tt>
|
|
method. It accepts an associative array of parameters, all of which are
|
|
optional:</p>
|
|
<table border="1" class="docutils">
|
|
<colgroup>
|
|
<col width="15%" />
|
|
<col width="85%" />
|
|
</colgroup>
|
|
<thead valign="bottom">
|
|
<tr class="row-odd"><th class="head">Option</th>
|
|
<th class="head">Possible values</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody valign="top">
|
|
<tr class="row-even"><td>driver</td>
|
|
<td>‘mcrypt’, ‘openssl’</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>cipher</td>
|
|
<td>Cipher name (see <a class="reference internal" href="#ciphers-and-modes"><em>Supported encryption ciphers and modes</em></a>)</td>
|
|
</tr>
|
|
<tr class="row-even"><td>mode</td>
|
|
<td>Encryption mode (see <a class="reference internal" href="#encryption-modes"><em>Encryption modes</em></a>)</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>key</td>
|
|
<td>Encryption key</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>For example, if you were to change the encryption algorithm and
|
|
mode to AES-256 in CTR mode, this is what you should do:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">initialize</span><span class="p">(</span>
|
|
<span class="k">array</span><span class="p">(</span>
|
|
<span class="s1">'cipher'</span> <span class="o">=></span> <span class="s1">'aes-256'</span><span class="p">,</span>
|
|
<span class="s1">'mode'</span> <span class="o">=></span> <span class="s1">'ctr'</span><span class="p">,</span>
|
|
<span class="s1">'key'</span> <span class="o">=></span> <span class="s1">'<a 32-character random string>'</span>
|
|
<span class="p">)</span>
|
|
<span class="p">);</span>
|
|
</pre></div>
|
|
</div>
|
|
<p>Note that we only mentioned that you want to change the ciper and mode,
|
|
but we also included a key in the example. As previously noted, it is
|
|
important that you choose a key with a proper size for the used algorithm.</p>
|
|
<p>There’s also the ability to change the driver, if for some reason you
|
|
have both, but want to use MCrypt instead of OpenSSL:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="c1">// Switch to the MCrypt driver</span>
|
|
<span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">initialize</span><span class="p">(</span><span class="k">array</span><span class="p">(</span><span class="s1">'driver'</span> <span class="o">=></span> <span class="s1">'mcrypt'</span><span class="p">));</span>
|
|
|
|
<span class="c1">// Switch back to the OpenSSL driver</span>
|
|
<span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">initialize</span><span class="p">(</span><span class="k">array</span><span class="p">(</span><span class="s1">'driver'</span> <span class="o">=></span> <span class="s1">'openssl'</span><span class="p">));</span>
|
|
</pre></div>
|
|
</div>
|
|
</div>
|
|
<div class="section" id="encrypting-and-decrypting-data">
|
|
<h3><a class="toc-backref" href="#id12">Encrypting and decrypting data</a><a class="headerlink" href="#encrypting-and-decrypting-data" title="Permalink to this headline">¶</a></h3>
|
|
<p>Encrypting and decrypting data with the already configured library
|
|
settings is simple. As simple as just passing the string to the
|
|
<tt class="docutils literal"><span class="pre">encrypt()</span></tt> and/or <tt class="docutils literal"><span class="pre">decrypt()</span></tt> methods:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$plain_text</span> <span class="o">=</span> <span class="s1">'This is a plain-text message!'</span><span class="p">;</span>
|
|
<span class="nv">$ciphertext</span> <span class="o">=</span> <span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">encrypt</span><span class="p">(</span><span class="nv">$plain_text</span><span class="p">);</span>
|
|
|
|
<span class="c1">// Outputs: This is a plain-text message!</span>
|
|
<span class="k">echo</span> <span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">decrypt</span><span class="p">(</span><span class="nv">$ciphertext</span><span class="p">);</span>
|
|
</pre></div>
|
|
</div>
|
|
<p>And that’s it! The Encryption library will do everything necessary
|
|
for the whole process to be cryptographically secure out-of-the-box.
|
|
You don’t need to worry about it.</p>
|
|
<div class="admonition important">
|
|
<p class="first admonition-title">Important</p>
|
|
<p class="last">Both methods will return FALSE in case of an error.
|
|
While for <tt class="docutils literal"><span class="pre">encrypt()</span></tt> this can only mean incorrect
|
|
configuration, you should always check the return value
|
|
of <tt class="docutils literal"><span class="pre">decrypt()</span></tt> in production code.</p>
|
|
</div>
|
|
<div class="section" id="how-it-works">
|
|
<h4><a class="toc-backref" href="#id13">How it works</a><a class="headerlink" href="#how-it-works" title="Permalink to this headline">¶</a></h4>
|
|
<p>If you must know how the process works, here’s what happens under
|
|
the hood:</p>
|
|
<ul class="simple">
|
|
<li><tt class="docutils literal"><span class="pre">$this->encryption->encrypt($plain_text)</span></tt><ol class="arabic">
|
|
<li>Derive an encryption key and a HMAC key from your configured
|
|
<em>encryption_key</em> via HKDF, using the SHA-512 digest algorithm.</li>
|
|
<li>Generate a random initialization vector (IV).</li>
|
|
<li>Encrypt the data via AES-128 in CBC mode (or another previously
|
|
configured cipher and mode), using the above-mentioned derived
|
|
encryption key and IV.</li>
|
|
<li>Prepend said IV to the resulting cipher-text.</li>
|
|
<li>Base64-encode the resulting string, so that it can be safely
|
|
stored or transferred without worrying about character sets.</li>
|
|
<li>Create a SHA-512 HMAC authentication message using the derived
|
|
HMAC key to ensure data integrity and prepend it to the Base64
|
|
string.</li>
|
|
</ol>
|
|
</li>
|
|
<li><tt class="docutils literal"><span class="pre">$this->encryption->decrypt($ciphertext)</span></tt><ol class="arabic">
|
|
<li>Derive an encryption key and a HMAC key from your configured
|
|
<em>encryption_key</em> via HKDF, using the SHA-512 digest algorithm.
|
|
Because your configured <em>encryption_key</em> is the same, this
|
|
will produce the same result as in the <tt class="docutils literal"><span class="pre">encrypt()</span></tt> method
|
|
above - otherwise you won’t be able to decrypt it.</li>
|
|
<li>Check if the string is long enough, separate the HMAC out of
|
|
it and validate if it is correct (this is done in a way that
|
|
prevents timing attacks against it). Return FALSE if either of
|
|
the checks fails.</li>
|
|
<li>Base64-decode the string.</li>
|
|
<li>Separate the IV out of the cipher-text and decrypt the said
|
|
cipher-text using that IV and the derived encryption key.</li>
|
|
</ol>
|
|
</li>
|
|
</ul>
|
|
</div>
|
|
<div class="section" id="using-custom-parameters">
|
|
<span id="custom-parameters"></span><h4><a class="toc-backref" href="#id14">Using custom parameters</a><a class="headerlink" href="#using-custom-parameters" title="Permalink to this headline">¶</a></h4>
|
|
<p>Let’s say you have to interact with another system that is out
|
|
of your control and uses another method to encrypt data. A
|
|
method that will most certainly not match the above-described
|
|
sequence and probably not use all of the steps either.</p>
|
|
<p>The Encryption library allows you to change how its encryption
|
|
and decryption processes work, so that you can easily tailor a
|
|
custom solution for such situations.</p>
|
|
<div class="admonition note">
|
|
<p class="first admonition-title">Note</p>
|
|
<p class="last">It is possible to use the library in this way, without
|
|
setting an <em>encryption_key</em> in your configuration file.</p>
|
|
</div>
|
|
<p>All you have to do is to pass an associative array with a few
|
|
parameters to either the <tt class="docutils literal"><span class="pre">encrypt()</span></tt> or <tt class="docutils literal"><span class="pre">decrypt()</span></tt> method.
|
|
Here’s an example:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="c1">// Assume that we have $ciphertext, $key and $hmac_key</span>
|
|
<span class="c1">// from on outside source</span>
|
|
|
|
<span class="nv">$message</span> <span class="o">=</span> <span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">decrypt</span><span class="p">(</span>
|
|
<span class="nv">$ciphertext</span><span class="p">,</span>
|
|
<span class="k">array</span><span class="p">(</span>
|
|
<span class="s1">'cipher'</span> <span class="o">=></span> <span class="s1">'blowfish'</span><span class="p">,</span>
|
|
<span class="s1">'mode'</span> <span class="o">=></span> <span class="s1">'cbc'</span><span class="p">,</span>
|
|
<span class="s1">'key'</span> <span class="o">=></span> <span class="nv">$key</span><span class="p">,</span>
|
|
<span class="s1">'hmac_digest'</span> <span class="o">=></span> <span class="s1">'sha256'</span><span class="p">,</span>
|
|
<span class="s1">'hmac_key'</span> <span class="o">=></span> <span class="nv">$hmac_key</span>
|
|
<span class="p">)</span>
|
|
<span class="p">);</span>
|
|
</pre></div>
|
|
</div>
|
|
<p>In the above example, we are decrypting a message that was encrypted
|
|
using the Blowfish cipher in CBC mode and authenticated via a SHA-256
|
|
HMAC.</p>
|
|
<div class="admonition important">
|
|
<p class="first admonition-title">Important</p>
|
|
<p class="last">Note that both ‘key’ and ‘hmac_key’ are used in this
|
|
example. When using custom parameters, encryption and HMAC keys
|
|
are not derived like the default behavior of the library is.</p>
|
|
</div>
|
|
<p>Below is a list of the available options.</p>
|
|
<p>However, unless you really need to and you know what you are doing,
|
|
we advise you to not change the encryption process as this could
|
|
impact security, so please do so with caution.</p>
|
|
<table border="1" class="docutils">
|
|
<colgroup>
|
|
<col width="12%" />
|
|
<col width="14%" />
|
|
<col width="26%" />
|
|
<col width="49%" />
|
|
</colgroup>
|
|
<thead valign="bottom">
|
|
<tr class="row-odd"><th class="head">Option</th>
|
|
<th class="head">Default value</th>
|
|
<th class="head">Mandatory / Optional</th>
|
|
<th class="head">Description</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody valign="top">
|
|
<tr class="row-even"><td>cipher</td>
|
|
<td>N/A</td>
|
|
<td>Yes</td>
|
|
<td>Encryption algorithm (see <a class="reference internal" href="#ciphers-and-modes"><em>Supported encryption ciphers and modes</em></a>).</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>mode</td>
|
|
<td>N/A</td>
|
|
<td>Yes</td>
|
|
<td>Encryption mode (see <a class="reference internal" href="#encryption-modes"><em>Encryption modes</em></a>).</td>
|
|
</tr>
|
|
<tr class="row-even"><td>key</td>
|
|
<td>N/A</td>
|
|
<td>Yes</td>
|
|
<td>Encryption key.</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>hmac</td>
|
|
<td>TRUE</td>
|
|
<td>No</td>
|
|
<td>Whether to use a HMAC.
|
|
Boolean. If set to FALSE, then <em>hmac_digest</em> and
|
|
<em>hmac_key</em> will be ignored.</td>
|
|
</tr>
|
|
<tr class="row-even"><td>hmac_digest</td>
|
|
<td>sha512</td>
|
|
<td>No</td>
|
|
<td>HMAC message digest algorithm (see <a class="reference internal" href="#digests"><em>Supported HMAC authentication algorithms</em></a>).</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>hmac_key</td>
|
|
<td>N/A</td>
|
|
<td>Yes, unless <em>hmac</em> is FALSE</td>
|
|
<td>HMAC key.</td>
|
|
</tr>
|
|
<tr class="row-even"><td>raw_data</td>
|
|
<td>FALSE</td>
|
|
<td>No</td>
|
|
<td>Whether the cipher-text should be raw.
|
|
Boolean. If set to TRUE, then Base64 encoding and
|
|
decoding will not be performed and HMAC will not
|
|
be a hexadecimal string.</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<div class="admonition important">
|
|
<p class="first admonition-title">Important</p>
|
|
<p class="last"><tt class="docutils literal"><span class="pre">encrypt()</span></tt> and <tt class="docutils literal"><span class="pre">decrypt()</span></tt> will return FALSE if
|
|
a mandatory parameter is not provided or if a provided
|
|
value is incorrect. This includes <em>hmac_key</em>, unless <em>hmac</em>
|
|
is set to FALSE.</p>
|
|
</div>
|
|
</div>
|
|
<div class="section" id="supported-hmac-authentication-algorithms">
|
|
<span id="digests"></span><h4><a class="toc-backref" href="#id15">Supported HMAC authentication algorithms</a><a class="headerlink" href="#supported-hmac-authentication-algorithms" title="Permalink to this headline">¶</a></h4>
|
|
<p>For HMAC message authentication, the Encryption library supports
|
|
usage of the SHA-2 family of algorithms:</p>
|
|
<table border="1" class="docutils">
|
|
<colgroup>
|
|
<col width="19%" />
|
|
<col width="34%" />
|
|
<col width="47%" />
|
|
</colgroup>
|
|
<thead valign="bottom">
|
|
<tr class="row-odd"><th class="head">Algorithm</th>
|
|
<th class="head">Raw length (bytes)</th>
|
|
<th class="head">Hex-encoded length (bytes)</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody valign="top">
|
|
<tr class="row-even"><td>sha512</td>
|
|
<td>64</td>
|
|
<td>128</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>sha384</td>
|
|
<td>48</td>
|
|
<td>96</td>
|
|
</tr>
|
|
<tr class="row-even"><td>sha256</td>
|
|
<td>32</td>
|
|
<td>64</td>
|
|
</tr>
|
|
<tr class="row-odd"><td>sha224</td>
|
|
<td>28</td>
|
|
<td>56</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>The reason for not including other popular algorithms, such as
|
|
MD5 or SHA1 is that they are no longer considered secure enough
|
|
and as such, we don’t want to encourage their usage.
|
|
If you absolutely need to use them, it is easy to do so via PHP’s
|
|
native <a class="reference external" href="http://php.net/manual/en/function.hash-hmac.php">hash_hmac()</a> function.</p>
|
|
<p>Stronger algorithms of course will be added in the future as they
|
|
appear and become widely available.</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="section" id="class-reference">
|
|
<h2><a class="toc-backref" href="#id16">Class Reference</a><a class="headerlink" href="#class-reference" title="Permalink to this headline">¶</a></h2>
|
|
<dl class="class">
|
|
<dt id="CI_Encryption">
|
|
<em class="property">class </em><tt class="descname">CI_Encryption</tt><a class="headerlink" href="#CI_Encryption" title="Permalink to this definition">¶</a></dt>
|
|
<dd><dl class="method">
|
|
<dt id="CI_Encryption::initialize">
|
|
<tt class="descname">initialize</tt><big>(</big><em>$params</em><big>)</big><a class="headerlink" href="#CI_Encryption::initialize" title="Permalink to this definition">¶</a></dt>
|
|
<dd><table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
|
|
<li><strong>$params</strong> (<em>array</em>) – Configuration parameters</li>
|
|
</ul>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">CI_Encryption instance (method chaining)</p>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">CI_Encryption</p>
|
|
</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>Initializes (configures) the library to use a different
|
|
driver, cipher, mode or key.</p>
|
|
<p>Example:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">initialize</span><span class="p">(</span>
|
|
<span class="k">array</span><span class="p">(</span><span class="s1">'mode'</span> <span class="o">=></span> <span class="s1">'ctr'</span><span class="p">)</span>
|
|
<span class="p">);</span>
|
|
</pre></div>
|
|
</div>
|
|
<p>Please refer to the <a class="reference internal" href="#configuration"><em>Configuring the library</em></a> section for detailed info.</p>
|
|
</dd></dl>
|
|
|
|
<dl class="method">
|
|
<dt id="CI_Encryption::encrypt">
|
|
<tt class="descname">encrypt</tt><big>(</big><em>$data</em><span class="optional">[</span>, <em>$params = NULL</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#CI_Encryption::encrypt" title="Permalink to this definition">¶</a></dt>
|
|
<dd><table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
|
|
<li><strong>$data</strong> (<em>string</em>) – Data to encrypt</li>
|
|
<li><strong>$params</strong> (<em>array</em>) – Optional parameters</li>
|
|
</ul>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Encrypted data or FALSE on failure</p>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">string</p>
|
|
</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>Encrypts the input data and returns its ciphertext.</p>
|
|
<p>Example:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$ciphertext</span> <span class="o">=</span> <span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">encrypt</span><span class="p">(</span><span class="s1">'My secret message'</span><span class="p">);</span>
|
|
</pre></div>
|
|
</div>
|
|
<p>Please refer to the <a class="reference internal" href="#custom-parameters"><em>Using custom parameters</em></a> section for information
|
|
on the optional parameters.</p>
|
|
</dd></dl>
|
|
|
|
<dl class="method">
|
|
<dt id="CI_Encryption::decrypt">
|
|
<tt class="descname">decrypt</tt><big>(</big><em>$data</em><span class="optional">[</span>, <em>$params = NULL</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#CI_Encryption::decrypt" title="Permalink to this definition">¶</a></dt>
|
|
<dd><table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
|
|
<li><strong>$data</strong> (<em>string</em>) – Data to decrypt</li>
|
|
<li><strong>$params</strong> (<em>array</em>) – Optional parameters</li>
|
|
</ul>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Decrypted data or FALSE on failure</p>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">string</p>
|
|
</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>Decrypts the input data and returns it in plain-text.</p>
|
|
<p>Example:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="k">echo</span> <span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">decrypt</span><span class="p">(</span><span class="nv">$ciphertext</span><span class="p">);</span>
|
|
</pre></div>
|
|
</div>
|
|
<p>Please refer to the <a class="reference internal" href="#custom-parameters"><em>Using custom parameters</em></a> secrion for information
|
|
on the optional parameters.</p>
|
|
</dd></dl>
|
|
|
|
<dl class="method">
|
|
<dt id="CI_Encryption::create_key">
|
|
<tt class="descname">create_key</tt><big>(</big><em>$length</em><big>)</big><a class="headerlink" href="#CI_Encryption::create_key" title="Permalink to this definition">¶</a></dt>
|
|
<dd><table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
|
|
<li><strong>$length</strong> (<em>int</em>) – Output length</li>
|
|
</ul>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">A pseudo-random cryptographic key with the specified length, or FALSE on failure</p>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">string</p>
|
|
</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>Creates a cryptographic key by fetching random data from
|
|
the operating system’s sources (i.e. /dev/urandom).</p>
|
|
</dd></dl>
|
|
|
|
<dl class="method">
|
|
<dt id="CI_Encryption::hkdf">
|
|
<tt class="descname">hkdf</tt><big>(</big><em>$key</em><span class="optional">[</span>, <em>$digest = 'sha512'</em><span class="optional">[</span>, <em>$salt = NULL</em><span class="optional">[</span>, <em>$length = NULL</em><span class="optional">[</span>, <em>$info = ''</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#CI_Encryption::hkdf" title="Permalink to this definition">¶</a></dt>
|
|
<dd><table class="docutils field-list" frame="void" rules="none">
|
|
<col class="field-name" />
|
|
<col class="field-body" />
|
|
<tbody valign="top">
|
|
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
|
|
<li><strong>$key</strong> (<em>string</em>) – Input key material</li>
|
|
<li><strong>$digest</strong> (<em>string</em>) – A SHA-2 family digest algorithm</li>
|
|
<li><strong>$salt</strong> (<em>string</em>) – Optional salt</li>
|
|
<li><strong>$length</strong> (<em>int</em>) – Optional output length</li>
|
|
<li><strong>$info</strong> (<em>string</em>) – Optional context/application-specific info</li>
|
|
</ul>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">A pseudo-random key or FALSE on failure</p>
|
|
</td>
|
|
</tr>
|
|
<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">string</p>
|
|
</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>Derives a key from another, presumably weaker key.</p>
|
|
<p>This method is used internally to derive an encryption and HMAC key
|
|
from your configured <em>encryption_key</em>.</p>
|
|
<p>It is publicly available due to its otherwise general purpose. It is
|
|
described in <a class="reference external" href="https://tools.ietf.org/rfc/rfc5869.txt">RFC 5869</a>.</p>
|
|
<p>However, as opposed to the description in RFC 5869, this implementation
|
|
doesn’t support SHA1.</p>
|
|
<p>Example:</p>
|
|
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$hmac_key</span> <span class="o">=</span> <span class="nv">$this</span><span class="o">-></span><span class="na">encryption</span><span class="o">-></span><span class="na">hkdf</span><span class="p">(</span>
|
|
<span class="nv">$key</span><span class="p">,</span>
|
|
<span class="s1">'sha512'</span><span class="p">,</span>
|
|
<span class="k">NULL</span><span class="p">,</span>
|
|
<span class="k">NULL</span><span class="p">,</span>
|
|
<span class="s1">'authentication'</span>
|
|
<span class="p">);</span>
|
|
|
|
<span class="c1">// $hmac_key is a pseudo-random key with a length of 64 bytes</span>
|
|
</pre></div>
|
|
</div>
|
|
</dd></dl>
|
|
|
|
</dd></dl>
|
|
|
|
</div>
|
|
</div>
|
|
|
|
|
|
</div>
|
|
<footer>
|
|
|
|
<div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
|
|
|
|
<a href="file_uploading.html" class="btn btn-neutral float-right" title="File Uploading Class">Next <span class="fa fa-arrow-circle-right"></span></a>
|
|
|
|
|
|
<a href="encrypt.html" class="btn btn-neutral" title="Encrypt Class"><span class="fa fa-arrow-circle-left"></span> Previous</a>
|
|
|
|
</div>
|
|
|
|
|
|
<hr/>
|
|
|
|
<div role="contentinfo">
|
|
<p>
|
|
© Copyright 2014 - 2017, British Columbia Institute of Technology.
|
|
Last updated on Mar 20, 2017.
|
|
</p>
|
|
</div>
|
|
|
|
Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
|
|
|
|
</footer>
|
|
</div>
|
|
</div>
|
|
|
|
</section>
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
|
|
<script type="text/javascript">
|
|
var DOCUMENTATION_OPTIONS = {
|
|
URL_ROOT:'../',
|
|
VERSION:'3.1.4',
|
|
COLLAPSE_INDEX:false,
|
|
FILE_SUFFIX:'.html',
|
|
HAS_SOURCE: false
|
|
};
|
|
</script>
|
|
<script type="text/javascript" src="../_static/jquery.js"></script>
|
|
<script type="text/javascript" src="../_static/underscore.js"></script>
|
|
<script type="text/javascript" src="../_static/doctools.js"></script>
|
|
|
|
|
|
|
|
|
|
|
|
<script type="text/javascript" src="../_static/js/theme.js"></script>
|
|
|
|
|
|
|
|
|
|
<script type="text/javascript">
|
|
jQuery(function () {
|
|
SphinxRtdTheme.StickyNav.enable();
|
|
});
|
|
</script>
|
|
|
|
|
|
</body>
|
|
</html> |