diff --git a/simpleid/www/cache.inc.php b/simpleid/www/cache.inc.php
new file mode 100644
index 0000000..d555e73
--- /dev/null
+++ b/simpleid/www/cache.inc.php
@@ -0,0 +1,232 @@
+<?php
+/*
+ * SimpleID
+ *
+ * Copyright (C) Kelvin Mo 2007-9
+ *
+ * Includes code Drupal OpenID module (http://drupal.org/project/openid)
+ * Rowan Kerr <rowan@standardinteractive.com>
+ * James Walker <james@bryght.com>
+ *
+ * Copyright (C) Rowan Kerr and James Walker
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * 
+ * $Id$
+ */
+
+/**
+ * Functions for caching and persistence.
+ *
+ * @package simpleid
+ * @filesource
+ */
+ 
+/**
+ *  Stores data into the cache.
+ *
+ * @param string $type the type of data in the cache
+ * @param string $key an identifier
+ * @param mixed $data the data to store
+ * @param int $time if present, sets the modification time of the cache file to this
+ * time
+ */ 
+function cache_set($type, $key, $data, $time = NULL) {
+    $filename = _cache_get_name($type, $key);
+    if (!file_exists(dirname($filename))) mkdir(dirname($filename), 0775, true);
+    $file = fopen($filename, 'w');
+    fwrite($file, serialize($data));
+    fclose($file);
+    
+    if ($time != NULL) {
+        touch($filename, $time);
+    }
+}
+
+/**
+ * Obtains data from the cache.
+ *
+ * @param string $type the type of data in the cache
+ * @param string $key an identifier
+ * @return mixed the data associated with the type and key, or NULL if the cache
+ * does not contain the requested data.
+ */
+function cache_get($type, $key) {
+    $filename = _cache_get_name($type, $key);
+    
+    if (!file_exists($filename)) return NULL;
+    
+    return unserialize(file_get_contents($filename));
+}
+
+/**
+ * Obtains all data of a particular type from the cache.
+ *
+ * @param string $type the type of data in the cache
+ * @return mixed an array of data associated with the type, or NULL if the cache
+ * does not contain the requested data.
+ */
+function cache_get_all($type) {
+    $r = array();
+    
+    if (!is_dir(CACHE_DIR . '/' . $type)) return $r;
+    $dir = opendir(CACHE_DIR . '/' . $type);
+    
+    while (($file = readdir($dir)) !== false) {
+        $filename = CACHE_DIR . '/' . $type . '/' . $file;
+        
+        if (filetype($filename) != "file") continue;
+        
+        $r[] = unserialize(file_get_contents($filename));
+    }
+    
+    closedir($dir);
+    
+    return $r;
+}
+
+/**
+ * Deletes data from the cache.
+ *
+ * @param string $type the type of data in the cache
+ * @param string $key an identifier
+ */
+function cache_delete($type, $key) {
+    $filename = _cache_get_name($type, $key);
+    if (file_exists($filename)) unlink($filename);
+}
+
+/**
+ * Garbage collects data stored the cache.  Data is deleted if it was stored
+ * for longer than the specified expiry.
+ *
+ * This function is deprecated, use {@link cache_expire()}.
+ *
+ * @param int $expiry the expiry time, in seconds, after which data will be deleted
+ * @param string $type the type of data in the cache
+ * @deprecated
+ */
+function cache_gc($expiry, $type = NULL) {
+    if ($type == NULL) {
+        $dir = opendir(CACHE_DIR);
+
+        while (($file = readdir($dir)) !== false) {
+            $filename = CACHE_DIR . '/' . $file;
+            if (in_array(filetype($filename), array('dir', 'link')))
+                cache_gc($expiry, $file);
+        }
+    } else {
+        if (!is_dir(CACHE_DIR . '/' . $type)) return;
+        $dir = opendir(CACHE_DIR . '/' . $type);
+        while (($file = readdir($dir)) !== false) {
+            $filename = CACHE_DIR . '/' . $type . '/' . $file;
+        
+            if ((filetype($filename) == "file") && (filectime($filename) < time() - $expiry))
+                unlink($filename);
+        }
+    }
+    
+    closedir($dir);
+}
+
+/**
+ * Garbage collects data stored the cache.  Data is deleted if it was stored
+ * for longer than the specified expiry.
+ *
+ * The parameter to this function takes either an integer or an array.  If the
+ * parameter is an integer, everything in the cache older than the specified
+ * time (in seconds) will be deleted.  If the parameter is an array, 
+ * cache items of the type specified in the key to the array, older than the
+ * corresponding value will be deleted.
+ *
+ * This function is deprecated, use {@link cache_expire()}.
+ *
+ * @param int|array $params the expiry time, in seconds, after which data will be deleted,
+ * or an array specifiying the expiry time for each type
+ */
+function cache_expire($params) {
+
+    $dirs = array();
+    array_push($dirs, CACHE_DIR);
+    while (sizeof($dirs)) {
+        $dirname = array_pop($dirs);
+        if (($dir = opendir($dirname)) === false) {
+            continue;
+        }
+
+        while (($file = readdir($dir)) !== false) {
+            $expiry = NULL;
+            if ($file == '.' || $file == '..') {
+                continue;
+            }
+            $filename = $dirname . '/' . $file;
+
+            if (is_dir($filename)) {
+                array_push($dirs, $filename);
+                continue;
+            }
+
+            if (is_int($params)) {
+                $expiry = $params;
+            } elseif (is_array($params)) {
+                foreach ($params as $type => $param) {
+                    if (strpos($filename, $type) !== false) {
+                        $expiry = $param;
+                        break;
+                    }
+                }
+            }
+
+            if (!is_null($expiry) && (filetype($filename) == "file") && (filectime($filename) < time() - $expiry)) {
+                unlink($filename);
+            }
+        }
+
+        closedir($dir);
+    }
+}
+
+/**
+ * Returns the time remaining, in seconds, before the data associated with the
+ * type and key become subject to garbage collection by {@link cache_gc()}.
+ *
+ * @param string $type the type of data in the cache
+ * @param string $key an identifier
+ * @param int $expiry the expiry time, in seconds, which would be passed onto the
+ * {@link cache_gc()} function
+ * @return int the time remaining before expiry, rounded downwards,
+ * or zero if the cache does not contain the requested data
+ * @since 0.8
+ */
+function cache_ttl($type, $key, $expiry) {
+    $filename = _cache_get_name($type, $key);
+    
+    if (!file_exists($filename)) return 0;
+    
+    return filectime($filename) - (time() - $expiry) - 1;
+}
+
+/**
+ * Returns the name of the cache data file, given a type and an identifier.
+ *
+ * @param string $type the type of data in the cache
+ * @param string $key an identifier
+ * @return string a file name
+ */
+function _cache_get_name($type, $key) {
+    return CACHE_DIR . '/' . $type . '/' . md5($key) . '.cache';
+}
+
+?>