--- loncom/lti/ltiutils.pm	2017/12/09 16:24:03	1.2
+++ loncom/lti/ltiutils.pm	2018/01/04 12:09:42	1.4
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Utility functions for managing LON-CAPA LTI interactions 
 #
-# $Id: ltiutils.pm,v 1.2 2017/12/09 16:24:03 raeburn Exp $
+# $Id: ltiutils.pm,v 1.4 2018/01/04 12:09:42 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -51,7 +51,7 @@ use LONCAPA qw(:DEFAULT :match);
 #
 # When LON-CAPA is operating as a Provider, nonce checking 
 # occurs when a user in course context in another LMS (the 
-# Consumer launches an external tool to access a LON-CAPA URL: 
+# Consumer) launches an external tool to access a LON-CAPA URL: 
 # /adm/lti/ with LON-CAPA symb, map, or deep-link ID appended.
 #
 
@@ -314,20 +314,23 @@ sub verify_lis_item {
 # LON-CAPA as LTI Consumer
 #
 # Sign a request used to launch an instance of an external
-# too in a LON-CAPA course, using the key and secret supplied 
+# tool in a LON-CAPA course, using the key and secret supplied 
 # by the Tool Provider.
 # 
 
 sub sign_params {
-    my ($url,$key,$secret,$paramsref) = @_;
+    my ($url,$key,$secret,$sigmethod,$paramsref) = @_;
     return unless (ref($paramsref) eq 'HASH');
+    if ($sigmethod eq '') {
+        $sigmethod = 'HMAC-SHA1';
+    }
     my $nonce = Digest::SHA::sha1_hex(sprintf("%06x%06x",rand(0xfffff0),rand(0xfffff0)));
     my $request = Net::OAuth->request("request token")->new(
             consumer_key => $key,
             consumer_secret => $secret,
             request_url => $url,
             request_method => 'POST',
-            signature_method => 'HMAC-SHA1',
+            signature_method => $sigmethod,
             timestamp => time,
             nonce => $nonce,
             callback => 'about:blank',
@@ -444,7 +447,7 @@ sub get_tool_lock {
 #
 
 sub release_tool_lock {
-    my ($cdom,$cnum,$marker) = @_;
+    my ($cdom,$cnum,$marker,$name) = @_;
     #  remove lock
     my @del_lock = ($name."\0".$marker."\0".'lock');
     my $dellockoutcome=&Apache::lonnet::del('exttools',\@del_lock,$cdom,$cnum);