diff --git a/readme.txt b/readme.txt
index 5456ef9..0ece9ad 100644
--- a/readme.txt
+++ b/readme.txt
@@ -4,7 +4,7 @@ Donate link: https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_i
 Tags: cache, page cache, full page cache, nginx, memcached, apc, speed
 Requires at least: 3.0
 Tested up to: 4.2.1
-Stable tag: 1.8.1
+Stable tag: 1.8.2
 License: GPLv3
 License URI: http://www.gnu.org/licenses/gpl-3.0.html
 
@@ -125,6 +125,13 @@ Version numbering logic:
 * every .B version indicates new features.
 * every ..C indicates bugfixes for A.B version.
 
+= 1.8.2 =
+*2015-04-30*
+
+* sha1 key hashing made to be optional
+* added additional debug condition of WP_FFPC__DEBUG_MODE constant to be `true`
+
+
 = 1.8.1 =
 *2015-04-29*
 
diff --git a/wp-admin.css b/wp-admin.css
new file mode 100644
index 0000000..8132817
--- /dev/null
+++ b/wp-admin.css
@@ -0,0 +1,194 @@
+.plugin-admin dt {
+	margin-top: 2em;
+	font-weight:bold;
+}
+
+.plugin-admin fieldset {
+	display:block;
+	margin: 0;
+	padding: 0 1em 0 1em;
+	border: 1px solid #ccc;
+}
+
+.plugin-admin legend {
+	display: none;
+	visibility: hidden;
+}
+
+.plugin-admin .description {
+	display: block;
+	padding-top: 0.3em;
+}
+
+.plugin-admin .tabs {
+	padding:0;
+	margin: 0;
+	list-style-type: none;
+}
+
+.plugin-admin .tabs li  {
+	border-style: solid;
+	border-width: 1px 1px 1px 1px;
+	border-color: #ccc;
+	border-bottom-color: #ccc;
+	line-height: 120%;
+	display: inline-block;
+	padding: 0.5em 2em 0.5em 2em;
+	text-decoration: none;
+	margin-bottom: -1px;
+	-webkit-border-top-left-radius: 3px;
+	-webkit-border-top-right-radius: 3px;
+	border-top-left-radius: 3px;
+	border-top-right-radius: 3px;
+	background: #f1f1f1;
+	background-image: -webkit-gradient(linear,left bottom,left top,from(#ececec),to(#f9f9f9));
+	background-image: -webkit-linear-gradient(bottom,#ececec,#f9f9f9);
+	background-image: -moz-linear-gradient(bottom,#ececec,#f9f9f9);
+	background-image: -o-linear-gradient(bottom,#ececec,#f9f9f9);
+	background-image: linear-gradient(to top,#ececec,#f9f9f9);
+}
+
+.plugin-admin .tabs li a {
+	outline: none;
+	text-decoration: none;
+	font-size: 120%;
+}
+
+.plugin-admin .tabs li.ui-state-active {
+	background: #fff;
+	border-bottom-color: #fff;
+}
+
+.error p {
+	font-weight: bold;
+}
+
+.error-msg {
+	color: #990000;
+}
+
+.ok-msg {
+	color: #009900;
+}
+
+.clear {
+	clear:both;
+}
+
+.wp-ffpc-donation {
+	padding: 0.8em;
+	border: 1px solid #ccc;
+	background-color: #f6f6f6;
+	-webkit-border-radius: 3px;
+	border-radius: 3px;
+
+}
+
+.wp-ffpc-donation * {
+	display: inline;
+	line-height: 2em;
+}
+
+.wp-ffpc-donation .currency {
+	padding: 0 0 0 0.3em;
+
+}
+
+.wp-ffpc-donation .submit {
+	display: inline-block;
+	width: 74px;
+	height: 21px;
+}
+
+.wp-ffpc-donation .ui-slider {
+	position: relative;
+	text-align: left;
+	display: inline-block;
+	width: 16em;
+	margin: 0 2em 0 2em;
+	height: 0.4em;
+	background-color: #111;
+	border: 1px solid #ccc;
+	-webkit-border-radius: 3px;
+	border-radius: 3px;
+	background: #f1f1f1;
+}
+
+.wp-ffpc-donation .ui-slider .ui-slider-handle {
+	position: absolute;
+	z-index: 2;
+	width: 1.2em;
+	height: 1.2em;
+	margin-top: -0.4em;
+	cursor: default;
+	border: 1px solid #ccc;
+	-webkit-border-radius: 3px;
+	border-radius: 3px;
+	background: #f1f1f1;
+	background-image: -webkit-gradient(linear,left bottom,left top,from(#ececec),to(#f9f9f9));
+	background-image: -webkit-linear-gradient(bottom,#ececec,#f9f9f9);
+	background-image: -moz-linear-gradient(bottom,#ececec,#f9f9f9);
+	background-image: -o-linear-gradient(bottom,#ececec,#f9f9f9);
+	background-image: linear-gradient(to top,#ececec,#f9f9f9);
+	outline: none;
+}
+
+
+.button-warning {
+	display: inline-block;
+	text-decoration: none;
+	font-size: 12px;
+	line-height: 23px;
+	height: 24px;
+	margin: 0;
+	padding: 0 10px 1px;
+	cursor: pointer;
+	border-width: 1px;
+	border-style: solid;
+	-webkit-border-radius: 3px;
+	-webkit-appearance: none;
+	border-radius: 3px;
+	white-space: nowrap;
+	-webkit-box-sizing: border-box;
+	-moz-box-sizing:    border-box;
+	box-sizing:         border-box;
+	background: #f3f3f3;
+	background-image: -webkit-gradient(linear, left top, left bottom, from(#fefefe), to(#f4f4f4));
+	background-image: -webkit-linear-gradient(top, #fefefe, #f4f4f4);
+	background-image:    -moz-linear-gradient(top, #fefefe, #f4f4f4);
+	background-image:      -o-linear-gradient(top, #fefefe, #f4f4f4);
+	background-image:   linear-gradient(to bottom, #fefefe, #f4f4f4);
+	border-color: #bbb;
+ 	color: #900;
+	text-shadow: 0 1px 0 #fff;
+}
+
+.button-warning:hover,
+.button-warning:focus {
+	background: #f3f3f3;
+	background-image: -webkit-gradient(linear, left top, left bottom, from(#fff), to(#f3f3f3));
+	background-image: -webkit-linear-gradient(top, #fff, #f3f3f3);
+	background-image:    -moz-linear-gradient(top, #fff, #f3f3f3);
+	background-image:     -ms-linear-gradient(top, #fff, #f3f3f3);
+	background-image:      -o-linear-gradient(top, #fff, #f3f3f3);
+	background-image:   linear-gradient(to bottom, #fff, #f3f3f3);
+	border-color: #900;
+	color: #a00;
+	-webkit-box-shadow: 1px 1px 1px rgba(0,0,0,.2);
+	box-shadow: 1px 1px 1px rgba(0,0,0,.2);
+}
+
+.button-warning:active {
+	background: #eee;
+	background-image: -webkit-gradient(linear, left top, left bottom, from(#f4f4f4), to(#fefefe));
+	background-image: -webkit-linear-gradient(top, #f4f4f4, #fefefe);
+	background-image:    -moz-linear-gradient(top, #f4f4f4, #fefefe);
+	background-image:     -ms-linear-gradient(top, #f4f4f4, #fefefe);
+	background-image:      -o-linear-gradient(top, #f4f4f4, #fefefe);
+	background-image:   linear-gradient(to bottom, #f4f4f4, #fefefe);
+	border-color: #900;
+	color: #a00;
+	text-shadow: 0 -1px 0 #fff;
+	-webkit-box-shadow: inset 0 2px 5px -3px rgba( 0, 0, 0, 0.5 );
+ 	box-shadow: inset 0 2px 5px -3px rgba( 0, 0, 0, 0.5 );
+}
diff --git a/wp-ffpc-abstract.php b/wp-ffpc-abstract.php
index 4b12f86..bb0a77e 100644
--- a/wp-ffpc-abstract.php
+++ b/wp-ffpc-abstract.php
@@ -563,7 +563,7 @@ abstract class WP_FFPC_ABSTRACT {
 				wp_die( '<h1>Error:</h1>' . '<p>' . $message . '</p>' );
 				exit;
 			default:
-				if ( !defined( 'WP_DEBUG' ) && WP_DEBUG != true  )
+				if ( !defined( 'WP_DEBUG' ) || WP_DEBUG != true || !defined( 'WP_FFPC__DEBUG_MODE' ) || WP_FFPC__DEBUG_MODE != true )
 					return;
 				break;
 		}
diff --git a/wp-ffpc-backend.php b/wp-ffpc-backend.php
index 173a940..4aae169 100644
--- a/wp-ffpc-backend.php
+++ b/wp-ffpc-backend.php
@@ -140,7 +140,10 @@ class WP_FFPC_Backend {
 
 		$key_base = self::map_urimap($urimap, $this->options['key']);
 		/* data is string only with content, meta is not used in nginx */
-		$key = sha1 ($prefix . $key_base );
+		$key = $prefix . $key_base;
+		if ( isset($this->options['hashkey']) && $this->options['hashkey'] == true)
+			$key = sha1 ($prefix . $key_base );
+
 		$this->log ( sprintf( __translate__( 'original key configuration: %s', $this->plugin_constant ),  $this->options['key'] ) );
 		$this->log ( sprintf( __translate__( 'setting key for: %s', $this->plugin_constant ),  $key_base ) );
 		$this->log ( sprintf( __translate__( 'setting key to: %s', $this->plugin_constant ),  $key ) );
@@ -502,7 +505,7 @@ class WP_FFPC_Backend {
 				wp_die( '<h1>Error:</h1>' . '<p>' . $message . '</p>' );
 				exit;
 			default:
-				if ( !defined( 'WP_DEBUG' ) && WP_DEBUG != true  )
+				if ( !defined( 'WP_DEBUG' ) || WP_DEBUG != true || !defined( 'WP_FFPC__DEBUG_MODE' ) || WP_FFPC__DEBUG_MODE != true )
 					return;
 				break;
 		}
diff --git a/wp-ffpc-class.php b/wp-ffpc-class.php
index b1eacd2..0a3b218 100644
--- a/wp-ffpc-class.php
+++ b/wp-ffpc-class.php
@@ -70,11 +70,8 @@ class WP_FFPC extends WP_FFPC_ABSTRACT {
 		$this->plugin_url = plugin_dir_url( __FILE__ );
 		$this->plugin_dir = plugin_dir_path( __FILE__ );
 
-		$this->common_url = $this->plugin_url . self::common_slug;
-		$this->common_dir = $this->plugin_dir . self::common_slug;
-
 		$this->admin_css_handle = $this->plugin_constant . '-admin-css';
-		$this->admin_css_url = $this->common_url . 'wp-admin.css';
+		$this->admin_css_url = $this->plugin_url . 'wp-admin.css';
 	}
 
 	/**
@@ -574,13 +571,23 @@ class WP_FFPC extends WP_FFPC_ABSTRACT {
 					?></dl>
 				</dd>
 
+				<dt>
+					<label for="hashkey"><?php _e('SHA1 hash key', $this->plugin_constant); ?></label>
+				</dt>
+				<dd>
+					<input type="checkbox" name="hashkey" id="hashkey" value="1" <?php checked($this->options['hashkey'],true); ?> />
+					<span class="description"><?php _e('Occasionally URL can be too long to be used as key for the backend storage, especially with memcached. Turn on this feature to use SHA1 hash of the URL as key instead. Please be aware that you have to add ( or uncomment ) a line in nginx if you want nginx to fetch the data directly; for details, please see the nginx example tab.', $this->plugin_constant); ?>
+				</dd>
+
+
+
 			</dl>
 			</fieldset>
 
 			<fieldset id="<?php echo $this->plugin_constant ?>-debug">
 			<legend><?php _e( 'Debug & in-depth settings', $this->plugin_constant ); ?></legend>
 			<h3><?php _e('Notes', $this->plugin_constant);?></h3>
-			<p><?php _e('The former method of debug logging flag has been removed. In case you need debug log from WP-FFPC please set the <a href="http://codex.wordpress.org/WP_DEBUG">WP_DEBUG</a> constant `true`.<br /> This will enable NOTICE level messages apart from the WARNING level ones which are always displayed.', $this->plugin_constant); ?></p>
+			<p><?php _e('The former method of debug logging flag has been removed. In case you need debug log from WP-FFPC please set both the <a href="http://codex.wordpress.org/WP_DEBUG">WP_DEBUG</a> and the WP_FFPC__DEBUG_MODE constants `true` in wp-config.php.<br /> This will enable NOTICE level messages apart from the WARNING level ones which are always displayed.', $this->plugin_constant); ?></p>
 
 			<dl>
 				<dt>
diff --git a/wp-ffpc-nginx-sample.conf b/wp-ffpc-nginx-sample.conf
index 6754f75..ce6a628 100644
--- a/wp-ffpc-nginx-sample.conf
+++ b/wp-ffpc-nginx-sample.conf
@@ -71,7 +71,9 @@ MEMCACHED_SERVERS
 
 			default_type text/html;
 			set $memcached_raw_key data-$scheme://$host$request_uri;
-			set_sha1 $memcached_key $memcached_raw_key;
+			# uncomment the following line if you have enabled
+			# sha1 hash option
+			# set_sha1 $memcached_key $memcached_raw_key;
 			set $memcached_request 1;
 
 			if ($request_method = POST ) {
diff --git a/wp-ffpc.php b/wp-ffpc.php
index 5cada89..7efb1c2 100644
--- a/wp-ffpc.php
+++ b/wp-ffpc.php
@@ -3,7 +3,7 @@
 Plugin Name: WP-FFPC
 Plugin URI: https://github.com/petermolnar/wp-ffpc
 Description: WordPress in-memory full page cache plugin
-Version: 1.8.1
+Version: 1.8.2
 Author: Peter Molnar <hello@petermolnar.eu>
 Author URI: http://petermolnar.eu/
 License: GPLv3
@@ -56,6 +56,7 @@ $wp_ffpc_defaults = array (
 	'key'                 => '$scheme://$host$request_uri',
 	'comments_invalidate' => true,
 	'pingback_header'     => false,
+	'hashkey'             => false,
 );
 
-$wp_ffpc = new WP_FFPC ( 'wp-ffpc', '1.7.9', 'WP-FFPC', $wp_ffpc_defaults, 'PeterMolnar_WordPressPlugins_wp-ffpc_HU' , 'WP-FFPC' , 'FA3NT7XDVHPWU' );
+$wp_ffpc = new WP_FFPC ( 'wp-ffpc', '1.8.2', 'WP-FFPC', $wp_ffpc_defaults, 'PeterMolnar_WordPressPlugins_wp-ffpc_HU' , 'WP-FFPC' , 'FA3NT7XDVHPWU' );