removed election_type, added ballot_type and tally_type and added way…

…s to create such elections and checks to ensure verification is of the right type.

client/heliosclient.py

@@ -35,8 +35,8 @@ def params(self):
     params_json = self.get("/elections/params")
     return algs.ElGamal.fromJSONDict(utils.from_json(params_json))
 
-  def election_new(self, name, public_key):
-    election_id = self.post("/elections/new_3", {"name" : name, "public_key" : utils.to_json(public_key.toJSONDict())})
+  def election_new(self, name, public_key, ballot_type = 'homomorphic', tally_type = 'homomorphic'):
+    election_id = self.post("/elections/new_3", {"name" : name, "public_key" : utils.to_json(public_key.toJSONDict()), "ballot_type": ballot_type, "tally_type": tally_type})
     return election_id
 
   def election_get(self, election_id):

crypto/electionalgs.py

@@ -220,6 +220,8 @@ def __init__(self):
     self.voting_starts_at = None
     self.voting_ends_at = None
     self.openreg = False
+    self.ballot_type = False
+    self.tally_type = False
 
   def init_tally(self):
     return Tally(self)
@@ -231,10 +233,12 @@ def get_hash(self):
 
   def toJSONDict(self):
     return_value = {
+      'ballot_type' : self.ballot_type,
       'election_id' : self.election_id,
       'name' : self.name,
       'public_key' : self.pk.toJSONDict(),
       'questions' : self.questions,
+      'tally_type' : self.tally_type,
       'voting_starts_at' : self.voting_starts_at,
       'voting_ends_at' : self.voting_ends_at
     }
@@ -256,6 +260,8 @@ def fromJSONDict(cls, d):
     el.voting_starts_at = d['voting_starts_at']
     el.voting_ends_at = d['voting_ends_at']
     el.questions = d['questions']
+    el.ballot_type = d['ballot_type']
+    el.tally_type = d['tally_type']
 
     if d['public_key']:
       el.pk = algs.EGPublicKey.fromJSONDict(d['public_key'])

helios/json.py

@@ -130,4 +130,4 @@ def toJSONRecurse(item):
 
   def toJSON(self):
     # FIXME: factor in the JSON_FIELDS for the class
-    return json.dumps(self.toJSONDict())
+    return dumps(self.toJSONDict())

helios/models.py

@@ -17,7 +17,7 @@
 
 class Election(models.Model, JSONObject):
   # when JSON'ified
-  JSON_FIELDS = ['election_id', 'name', 'public_key', 'questions', 'voters_hash', 'openreg', 'voting_starts_at', 'voting_ends_at']
+  JSON_FIELDS = ['ballot_type', 'election_id', 'name', 'public_key', 'questions', 'tally_type', 'voters_hash', 'openreg', 'voting_starts_at', 'voting_ends_at']
 
   election_id = models.AutoField(primary_key=True)
 
@@ -52,8 +52,9 @@ class Election(models.Model, JSONObject):
   # decryption proof, a JSON object
   decryption_proof = JSONField(null=True)
 
-  # type of election (homomorphic, mixnet, possibly with more detail)
-  election_type = models.CharField(max_length=300, default='homomorphic')
+  # type of election
+  ballot_type = models.CharField(max_length=300, default='homomorphic')
+  tally_type = models.CharField(max_length=300, default='homomorphic')
 
   def toJSONDict(self):
     # JSON fields, no need!

helios/templates/ballot_verifier.html

@@ -34,12 +34,17 @@
   var encrypted_vote_json = jQuery.secureEvalJSON(audit_trail);
 
   // go get the election
-  Helios.get_election({'election_id' : encrypted_vote_json.election_id}, function(election_json) {
+  Helios.get_election({'election_id' : encrypted_vote_json.election_id}, function(election_json, election_raw_json) {
       // display election fingerprint
-      var election = HELIOS.Election.fromJSONObject(election_json);
+      var election = HELIOS.Election.fromJSONString(election_raw_json);
       var election_hash = election.get_hash();
       result_append("election fingerprint is " + election_hash);
 
+      // check if the election ballot_type is homomorphic
+      if (election.ballot_type != "homomorphic") {
+          result_append("WARNING: the ballot type for this election is not homomorphic. Verification may fail because this verifier is only set up to handle homomorphic ballots.");
+      }
+
       // display ballot fingerprint
       encrypted_vote = HELIOS.EncryptedVote.fromJSONObject(encrypted_vote_json, election);
       result_append("ballot fingerprint is " + encrypted_vote.get_hash());

helios/templates/election_view.html

@@ -40,9 +40,17 @@ <h3>Administration</h3>
 {% else %}
 {% if election.in_progress_p %}
 {% if election.get_sk %}
+{% ifequal election.tally_type "homomorphic" %}
 <li> <a href="{% url helios.views.one_election_drive_tally_chunk election_id=election.election_id %}">compute tally</a></li>
 {% else %}
+<li> custom tally</li>
+{% endifequal %}
+{% else %}
+{% ifequal election.tally_type "homomorphic" %}
 <li> <a href="{% url helios.views.one_election_drive_tally election_id=election.election_id %}">compute tally</a></li>
+{% else %}
+<li> custom tally</li>
+{% endifequal %}
 {% endif %}
 {% endif %}
 {% endif %}
@@ -101,7 +109,12 @@ <h2>Tally</h2>
 </ul>
 {% endfor %}
 
+{% ifequal election.tally_type "homomorphic" %}
 <a style="font-size: 14pt;" target="_blank" href="{% url helios.views.election_verifier %}">Audit the Election Tally</a><br />
+{% else %}
+<b>This election uses a custom tallying mechanism, which must be audited by the custom code.</b>
+{% endifequal %}
+
 <br /><br />
 {% endif %}
 

helios/templates/tally_verifier.html

@@ -40,11 +40,16 @@
     VOTER_LIST = [];
 
     // get the election data
-    Helios.get_election({'election_id' : election_id}, function(election_json) {
-        var election = HELIOS.Election.fromJSONObject(election_json);
+    Helios.get_election({'election_id' : election_id}, function(election_json, election_raw_json) {
+        var election = HELIOS.Election.fromJSONString(election_raw_json);
         ELECTION = election;
         result_append("Election: " + election.name);
 
+        if (election.tally_type != "homomorphic") {
+            result_append("PROBLEM: this election is not a straight-forward homomorphic-tally election. As a result, Helios cannot currently verify it.");
+            return;
+        }
+
         // hash it
         var election_hash = election.get_hash();
         result_append("Fingerprint: " + election_hash);

helios/templates/vote.html

@@ -51,10 +51,9 @@ <h3>Fingerprint: <span id="election_hash"></span></h3>
 };
 
 BOOTH.setup_election = function(election, raw_json) {
-  BOOTH.election = HELIOS.Election.fromJSONObject(election);
-
-  // compute the hash from the raw JSON
-  BOOTH.election_hash = b64_sha1(raw_json);
+  // use the raw JSON for safer hash computation
+  BOOTH.election = HELIOS.Election.fromJSONString(raw_json);  
+  BOOTH.election_hash = BOOTH.election.get_hash();
 
   $('#election_hash').html(BOOTH.election_hash);
 

helios/views.py

@@ -105,6 +105,11 @@ def election_new_3(request):
   voting_starts_at = request.POST.get('voting_starts_at', None)
   voting_ends_at = request.POST.get('voting_ends_at', None)
 
+  # election type is homomorphic. The type of the election determines
+  # how votes are tallied and verified.
+  ballot_type = request.POST.get('ballot_type', 'homomorphic')
+  tally_type = request.POST.get('tally_type', 'homomorphic')
+
   # we need a list of admins, or at least a public key
   if len(trustee) == 0 and not public_key:
     return HttpResponseServerError('Need a list of trustees or a public key')
@@ -120,7 +125,7 @@ def election_new_3(request):
   else:
     sk = None
 
-  election = Election.objects.create(election_type = 'homomorphic', name = name,
+  election = Election.objects.create(ballot_type = ballot_type, tally_type = tally_type, name = name,
                       admin = get_user(request), api_client= get_api_client(request),
 #                      voting_starts_at = utils.string_to_datetime(voting_starts_at),
 #                      voting_ends_at = utils.string_to_datetime(voting_ends_at),
@@ -509,13 +514,19 @@ def one_election_email_trustees(request, election):
 
 @election_admin(frozen=True)
 def one_election_compute_tally(request, election):
+  if election.tally_type != "homomorphic":
+    return HttpResponseRedirect(reverse(one_election_view,args=[election.election_id]))
+
   return HttpResponse("election compute tally %s" % election.election_id)
 
 @election_admin(frozen=True)
 def one_election_drive_tally(request, election):
   """
   JavaScript-based driver for the entire tallying process, now done in JavaScript.
   """
+  if election.tally_type != "homomorphic":
+    return HttpResponseRedirect(reverse(one_election_view,args=[election.election_id]))
+
   election_pk = election.public_key
   election_pk_json = utils.to_json(election_pk.toJSONDict())
 
@@ -586,7 +597,6 @@ def one_voter_delete(request, election, voter_id):
 
 @election_view(frozen=True)
 def one_voter_submit(request, election, voter_id):
-  import pdb; pdb.set_trace()
   election_obj = election.toElection()
 
   # this will raise an exception if the voter is bad

static/helios.js

@@ -72,18 +72,24 @@ HELIOS.Election = Class.extend({
     // in terms of ordering the keys. FIXME: get a JSON library that orders keys properly.
     if (this.openreg) {
       return {
-        election_id : this.election_id, name : this.name, openreg: true, public_key: this.pk.toJSONObject(), questions : this.questions,
-        voting_ends_at : this.voting_ends_at, voting_starts_at : this.voting_starts_at
+        ballot_type: this.ballot_type, election_id : this.election_id,
+        name : this.name, openreg: true, public_key: this.pk.toJSONObject(), questions : this.questions,
+        tally_type: this.tally_type, voting_ends_at : this.voting_ends_at, voting_starts_at : this.voting_starts_at
       };
     } else {
       return {
-        election_id : this.election_id, name : this.name, public_key: this.pk.toJSONObject(), questions : this.questions,
-        voters_hash : this.voters_hash, voting_ends_at : this.voting_ends_at, voting_starts_at : this.voting_starts_at
+        ballot_type: this.ballot_type, election_id : this.election_id,
+        name : this.name, public_key: this.pk.toJSONObject(), questions : this.questions,
+        tally_type: this.tally_type, voters_hash : this.voters_hash, voting_ends_at : this.voting_ends_at, voting_starts_at : this.voting_starts_at
       };      
     }
   },
 
   get_hash: function() {
+    if (this.election_hash)
+      return this.election_hash;
+
+    // otherwise  
     return b64_sha1(this.toJSON());
   },
 
@@ -93,12 +99,26 @@ HELIOS.Election = Class.extend({
   }
 });
 
+HELIOS.Election.fromJSONString = function(raw_json) {
+  var json_object = $.secureEvalJSON(raw_json);
+
+  // hash fix for the issue with re-json'ifying unicode chars
+  var election = HELIOS.Election.fromJSONObject(json_object);
+  election.election_hash = b64_sha1(raw_json);
+
+  return election;
+};
+
 HELIOS.Election.fromJSONObject = function(d) {
   var el = new HELIOS.Election();
   el.election_id = d.election_id;
   el.name = d.name; el.voters_hash = d.voters_hash; el.voting_starts_at = d.voting_starts_at; el.voting_ends_at = d.voting_ends_at;
   el.questions = d.questions;
 
+  // stuff about the election
+  el.ballot_type = d.ballot_type;
+  el.tally_type = d.tally_type;
+
   // empty questions
   if (!el.questions)
     el.questions = [];

tests/heliosclient.py

@@ -15,10 +15,10 @@
 # instantiate the client
 # modify variables here
 helios = heliosclient.HeliosClient({'consumer_key': 'test', 'consumer_secret': '123'},
-                        host = '174.129.241.146',
-#                        host = "localhost",
-                        port = 80,
-                        prefix = "/helios"
+#                        host = '174.129.241.146',
+                        host = "localhost",
+                        port = 8000,
+#                        prefix = "/helios"
                         )
 
 print "headers:\n"