Index: openacs-4/packages/xowf/lib/online-exam-answer.wf
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowf/lib/online-exam-answer.wf,v
diff -u -N -r1.2.2.8 -r1.2.2.9
--- openacs-4/packages/xowf/lib/online-exam-answer.wf	4 Nov 2019 10:24:39 -0000	1.2.2.8
+++ openacs-4/packages/xowf/lib/online-exam-answer.wf	6 Nov 2019 18:49:21 -0000	1.2.2.9
@@ -140,14 +140,18 @@
 
 Action review \
     -next_state done \
-    -label #xowf.online-exam-review#
+    -label #xowf.online-exam-review# \
+    -proc activate {obj} {
+      [[$obj wf_context ] wf_container] addSignature $obj
+    }
 
 Action save \
     -label #xowf.online-exam-save#
 
 Action logout \
     -label #xowf.online-exam-submit# \
     -proc activate {obj} {
+      [[$obj wf_context ] wf_container] addSignature $obj
       set pid [$obj package_id]
       set try_out_mode [$obj property try_out_mode 0]
       set return_url [$obj property return_url .]
@@ -217,14 +221,13 @@
 
 ########################################################################
 #
-# Helper methods for the workflow context
+# Helper methods for the workflow container
 #
 ########################################################################
 
 #
 # Field-renaming form loader
 #
-
 proc get_question_form_object {ctx form_name} {
   set obj [$ctx object]
 
@@ -248,7 +251,6 @@
   return $form_obj
 }
 
-
 #
 # Set "title" with question and user information.
 #
@@ -264,7 +266,7 @@
     lappend title $titleString
   }
   lappend title \
-      "[$obj title]" \
+      [$obj title] \
       "IP: [$obj property ip]"
   #ns_log notice "SETTING $obj title [join $title { · }] (Container)"
   $obj title [join $title " · "]
@@ -331,14 +333,25 @@
               -form_constraints [lsort -unique $fc]]
 }
 
+:proc addSignature {obj} {
+  set answerAttributes [xowf::test_item::renaming_form_loader \
+                            answer_attributes [$obj instance_attributes]]
+  set sha256 [ns_md string -digest sha256 $answerAttributes]
+  $obj set_property -new true signature $sha256
+  return $sha256
+}
+
+
 ########################################################################
 #
 # Object specific operations
 #
 ########################################################################
 
 :object-specific {
-  # ensure default value is updated for each instance individually
+  #
+  # Ensure default value is updated for each instance individually.
+  #
   Property ip -default [expr {[ns_conn isconnected] ? [ad_conn peeraddr] : "nowhere"}]
 
   set ctx [:wf_context]
Index: openacs-4/packages/xowf/lib/online-exam.wf
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowf/lib/online-exam.wf,v
diff -u -N -r1.6.2.9 -r1.6.2.10
--- openacs-4/packages/xowf/lib/online-exam.wf	4 Nov 2019 10:24:39 -0000	1.6.2.9
+++ openacs-4/packages/xowf/lib/online-exam.wf	6 Nov 2019 18:49:21 -0000	1.6.2.10
@@ -359,7 +359,9 @@
     set wf [[$ctx wf_container] get_answer_wf [self]]
     if {$wf ne ""} {
       set items [[$ctx wf_container] get_wf_instances $wf]
-
+      set withSignature [expr {[dict exists ${:instance_attributes} signature]
+                               ? [dict get ${:instance_attributes} signature]
+                               : 0 }]
       set examTitle ${:title}
       foreach i [$items children] {
         set uid [$i property _creation_user]
@@ -380,10 +382,24 @@
         #
         $i set __feedback_mode 2
         set question_form [$i render_content]
-
+        
+        if {$withSignature} {
+          set answerAttributes [xowf::test_item::renaming_form_loader \
+                                    answer_attributes [$i instance_attributes]]
+          set sha256 [ns_md string -digest sha256 $answerAttributes]
+          set signatureString "<div class='signature'>Aktuelle Signatur: $sha256</div>\n"
+          set submissionSignature [$i property signature ""]
+          if {$submissionSignature ne ""} {
+            append signatureString "<div>Abgabe Signatur: $submissionSignature<div>\n"
+          }
+        } else {
+          set signatureString ""
+        }
+        
         append HTML "\n<div class='single_exam'>" \
             "<h1>$examTitle - IP [$i property ip]</h1>" \
             "<h2>$userName · [::xo::get_user_name $uid] · $pretty_date</h2>" \
+            $signatureString \
             $question_form \
             "</div>\n"
       }