diff --git a/lib/Saml2/AuthnRequest.php b/lib/Saml2/AuthnRequest.php
index 706a315d..35eff436 100644
--- a/lib/Saml2/AuthnRequest.php
+++ b/lib/Saml2/AuthnRequest.php
@@ -77,12 +77,19 @@ public function __construct(OneLogin_Saml2_Settings $settings)
     <samlp:NameIDPolicy
         Format="{$nameIDPolicyFormat}"
         AllowCreate="true" />
-    <samlp:RequestedAuthnContext Comparison="exact">
-        <saml:AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport</saml:AuthnContextClassRef>
-    </samlp:RequestedAuthnContext>    
-</samlp:AuthnRequest>
 AUTHNREQUEST;
 
+        if (!isset($security['allowedAuthContexts'])) 
+            $security['allowedAuthContexts'] = array('urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport');
+        if($security['allowedAuthContexts'] && is_array($security['allowedAuthContexts']))
+        {
+            $request .= '<samlp:RequestedAuthnContext Comparison="exact">'."\n";
+            foreach($security['allowedAuthContexts'] as $authCtx) 
+                $request .= '<saml:AuthnContextClassRef>'.$authCtx."</saml:AuthnContextClassRef>\n";
+            $request .= '</samlp:RequestedAuthnContext> '."\n";
+        }
+        $request .= '</samlp:AuthnRequest>';
+
         $this->_id = $id;
         $this->_authnRequest = $request;
     }
diff --git a/lib/Saml2/LogoutRequest.php b/lib/Saml2/LogoutRequest.php
index f78720d0..b7754fc5 100644
--- a/lib/Saml2/LogoutRequest.php
+++ b/lib/Saml2/LogoutRequest.php
@@ -305,15 +305,16 @@ public function isValid()
                     $signAlg = $_GET['SigAlg'];
                 }
 
-                $signedQuery = 'SAMLRequest='.urlencode($_GET['SAMLRequest']);
-                if (isset($_GET['RelayState'])) {
-                    $signedQuery .= '&RelayState='.urlencode($_GET['RelayState']);
-                }
-                $signedQuery .= '&SigAlg='.urlencode($signAlg);
-
+                $signedQuery = 'SAMLRequest='.OneLogin_Saml2_Utils::extractOriginalQueryParam('SAMLRequest');
+                if (isset($_GET['RelayState'])) 
+                    $signedQuery .= '&RelayState='.OneLogin_Saml2_Utils::extractOriginalQueryParam('RelayState');
+                
+                $signedQuery .= '&SigAlg='.OneLogin_Saml2_Utils::extractOriginalQueryParam('SigAlg');
+                
                 if (!isset($idpData['x509cert']) || empty($idpData['x509cert'])) {
                     throw new Exception('In order to validate the sign on the Logout Request, the x509cert of the IdP is required');
                 }
+                
                 $cert = $idpData['x509cert'];
 
                 $objKey = new XMLSecurityKey(XMLSecurityKey::RSA_SHA1, array('type' => 'public'));
diff --git a/lib/Saml2/Response.php b/lib/Saml2/Response.php
index fe31ecfe..c2810f8f 100644
--- a/lib/Saml2/Response.php
+++ b/lib/Saml2/Response.php
@@ -108,7 +108,7 @@ public function isValid($requestId = null)
                 $signNodes = $this->document->getElementsByTagName('Signature');
             }
             foreach ($signNodes as $signNode) {
-                $signedElements[] = $signNode->parentNode->tagName;
+                $signedElements[] = $signNode->parentNode->localName;
             }
 
             if (!empty($signedElements)) {
@@ -241,11 +241,11 @@ public function isValid($requestId = null)
                     throw new Exception("A valid SubjectConfirmation was not found on this Response");
                 }
 
-                if ($security['wantAssertionsSigned'] && !in_array('saml:Assertion', $signedElements)) {
+                if ($security['wantAssertionsSigned'] && !in_array('Assertion', $signedElements)) {
                     throw new Exception("The Assertion of the Response is not signed and the SP requires it");
                 }
-                
-                if ($security['wantMessagesSigned'] && !in_array('samlp:Response', $signedElements)) {
+
+                if ($security['wantMessagesSigned'] && !in_array('Response', $signedElements)) {
                     throw new Exception("The Message of the Response is not signed and the SP requires it");
                 }
             }
@@ -255,7 +255,7 @@ public function isValid($requestId = null)
                 $fingerprint = $idpData['certFingerprint'];
 
                 // Only validates the first signed element
-                if (in_array('samlp:Response', $signedElements)) {
+                if (in_array('Response', $signedElements)) {
                     $documentToValidate = $this->document;
                 } else {
                     $documentToValidate = $signNodes->item(0)->parentNode;
@@ -463,7 +463,9 @@ public function getAttributes()
 
             $attributeValues = array();
             foreach ($entry->childNodes as $childNode) {
-                if ($childNode->nodeType == XML_ELEMENT_NODE && $childNode->tagName === $childNode->prefix.':AttributeValue') {
+                $tagName = ($childNode->prefix ? $childNode->prefix.':' : '') . 'AttributeValue';
+                if ($childNode->nodeType == XML_ELEMENT_NODE && $childNode->tagName === $tagName) {
+
                     $attributeValues[] = $childNode->nodeValue;
                 }
             }
@@ -523,9 +525,9 @@ public function validateSignedElements($signedElements)
             return false;
         }
         $ocurrence = array_count_values($signedElements);
-        if ((in_array('samlp:Response', $signedElements) && $ocurrence['samlp:Response'] > 1) ||
-            (in_array('saml:Assertion', $signedElements) && $ocurrence['saml:Assertion'] > 1) ||
-            !in_array('samlp:Response', $signedElements) && !in_array('saml:Assertion', $signedElements)
+        if ((in_array('Response', $signedElements) && $ocurrence['Response'] > 1) ||
+            (in_array('Assertion', $signedElements) && $ocurrence['Assertion'] > 1) ||
+            !in_array('Response', $signedElements) && !in_array('Assertion', $signedElements)
         ) {
             return false;
         }
diff --git a/lib/Saml2/Utils.php b/lib/Saml2/Utils.php
index 0342a668..2bc3e993 100644
--- a/lib/Saml2/Utils.php
+++ b/lib/Saml2/Utils.php
@@ -944,7 +944,18 @@ public static function addSign($xml, $key, $cert)
         return $signedxml;
     }
 
-
+    /**
+     * Extract a query param - as it was sent - from $_SERVER[QUERY_STRING]
+     *
+     * @param string The param to-be extracted
+     */
+    public static function extractOriginalQueryParam ($name)
+    {
+        $index = strpos($_SERVER['QUERY_STRING'], $name.'=');
+        $substring = substr($_SERVER['QUERY_STRING'], $index + strlen($name) + 1);
+        $end = strpos($substring, '&');
+        return $end ? substr($substring, 0, strpos($substring, '&')) : $substring;
+    }
 
 
     /**