Add mixnets to election workflow

eos/base/workflow.py

@@ -61,7 +61,7 @@ class WorkflowTask(EmbeddedObject):
 	
 	@classmethod
 	def satisfies(cls, descriptor):
-		return cls._name == descriptor or descriptor in cls.provides
+		return cls._name == descriptor or descriptor in cls.provides or (descriptor in EosObject.objects and issubclass(cls, EosObject.objects[descriptor]))
 	
 	def on_enter(self):
 		self.exit()

eos/core/objects/__init__.py

@@ -71,7 +71,6 @@ class PrimitiveField(Field):
 
 DictField = PrimitiveField
 IntField = PrimitiveField
-ListField = PrimitiveField
 StringField = PrimitiveField
 
 class EmbeddedObjectField(Field):
@@ -161,8 +160,10 @@ class EosObject(metaclass=EosObjectType):
 	@staticmethod
 	def serialise_and_wrap(value, object_type=None):
 		if object_type:
+			if value:
 				return value.serialise()
-		return {'type': value._name, 'value': value.serialise()}
+			return None
+		return {'type': value._name, 'value': (value.serialise() if value else None)}
 	
 	@staticmethod
 	def deserialise_and_unwrap(value, object_type=None):
@@ -206,6 +207,13 @@ class EosList(EosObject):
 		
 		self.impl = list(*args)
 	
+	def post_init(self):
+		for i in range(len(self.impl)):
+			val = self.impl[i]
+			val._instance = (self, i)
+			if not val._inited:
+				val.post_init()
+	
 	# Lists in JS are implemented as native Arrays, so no cheating here :(
 	def __len__(self):
 		return len(self.impl)

eos/psr/election.py

@@ -14,6 +14,7 @@
 #   You should have received a copy of the GNU Affero General Public License
 #   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+from eos.core.bigint import *
 from eos.core.objects import *
 from eos.base.election import *
 from eos.psr.bitstream import *
@@ -46,9 +47,16 @@ class Trustee(EmbeddedObject):
 	name = StringField()
 	email = StringField()
 
+class MixChallengeResponse(EmbeddedObject):
+	index = IntField()
+	reenc = EmbeddedObjectListField(BigInt)
+	rand = EmbeddedObjectField(BigInt)
+
 class MixingTrustee(Trustee):
-	mix_order = IntField()
+	mixed_questions = ListField(EmbeddedObjectListField(BlockEncryptedAnswer))
-	mixed_questions = EmbeddedObjectListField()
+	commitments = ListField(EmbeddedObjectListField(BigInt))
+	challenge = EmbeddedObjectField(BigInt)
+	response = ListField(EmbeddedObjectListField(MixChallengeResponse))
 
 class PSRElection(Election):
 	_db_name = Election._name

eos/psr/mixnet.py

@@ -19,7 +19,11 @@ from eos.core.objects import *
 from eos.psr.election import *
 
 class RPCMixnet:
-	def __init__(self):
+	def __init__(self, mix_order):
+		self.mix_order = mix_order
+		
+		self.is_left = (self.mix_order % 2 == 0)
+		
 		self.params = []
 	
 	def random_permutation(self, n):
@@ -54,26 +58,26 @@ class RPCMixnet:
 			# Record the parameters
 			permutations_and_reenc.append([permutations[i], block_reencryptions, block.public_key.group.random_element(), block.public_key.group.random_element()])
 		
-		commitments_left = []
+		commitments = []
+		if self.is_left:
 			for i in range(len(permutations_and_reenc)):
 				val = permutations_and_reenc[i]
-			val_json = [val[0], [str(x) for x in val[1]], str(val[2])]
+				val_obj = MixChallengeResponse(index=val[0], reenc=val[1], rand=val[2])
-			commitments_left.append(EosObject.to_sha256(EosObject.to_json(val_json))[0])
+				commitments.append(EosObject.to_sha256(EosObject.to_json(val_obj.serialise()))[1])
-		
+		else:
-		commitments_right = []
 			for i in range(len(permutations_and_reenc)):
 				# Find the answer that went to 'i'
 				idx = next(idx for idx in range(len(permutations_and_reenc)) if permutations_and_reenc[idx][0] == i)
 				val = permutations_and_reenc[idx]
 				
-			val_json = [idx, [str(x) for x in val[1]], str(val[3])]
+				val_obj = MixChallengeResponse(index=idx, reenc=val[1], rand=val[3])
-			commitments_right.append(EosObject.to_sha256(EosObject.to_json(val_json))[0])
+				commitments.append(EosObject.to_sha256(EosObject.to_json(val_obj.serialise()))[1])
 		
 		self.params = permutations_and_reenc
-		return shuffled_answers, commitments_left, commitments_right
+		return shuffled_answers, commitments
 	
-	def challenge(self, i, is_left):
+	def challenge(self, i):
-		if is_left:
+		if self.is_left:
 			val = self.params[i]
 			return [val[0], val[1], val[2]]
 		else:

eos/psr/tests.py

@@ -119,7 +119,7 @@ class MixnetTestCase(EosTestCase):
 		
 		# Generate plaintexts
 		pts = []
-		for i in range(10):
+		for i in range(4):
 			pts.append(sk.public_key.group.random_element())
 		
 		# Encrypt plaintexts
@@ -130,11 +130,12 @@ class MixnetTestCase(EosTestCase):
 			ct = bs.map(sk.public_key.encrypt, sk.public_key.group.p.nbits() - 1)
 			answers.append(BlockEncryptedAnswer(blocks=ct))
 		
+		def do_mixnet(mix_order):
 			# Set up mixnet
-		mixnet = RPCMixnet()
+			mixnet = RPCMixnet(mix_order)
 			
 			# Mix answers
-		shuffled_answers, commitments_left, commitments_right = mixnet.shuffle(answers)
+			shuffled_answers, commitments = mixnet.shuffle(answers)
 			
 			# Decrypt shuffle
 			msgs = []
@@ -155,19 +156,24 @@ class MixnetTestCase(EosTestCase):
 					self.assertEqual(claimed_blocks[j].delta, reencrypted_block.delta)
 			
 			for i in range(len(pts)):
-			# Left
+				perm, reencs, rand = mixnet.challenge(i)
-			perm, reencs, rand = mixnet.challenge(i, True)
+				val_obj = MixChallengeResponse(index=perm, reenc=reencs, rand=rand)
-			val_json = [perm, [str(x) for x in reencs], str(rand)]
+				self.assertEqual(commitments[i], EosObject.to_sha256(EosObject.to_json(val_obj.serialise()))[1])
-			self.assertEqual(commitments_left[i], EosObject.to_sha256(EosObject.to_json(val_json))[0])
-			verify_shuffle(i, perm, reencs)
 				
-			# Right
+				if mixnet.is_left:
-			perm, reencs, rand = mixnet.challenge(i, False)
+					verify_shuffle(i, perm, reencs)
-			val_json = [perm, [str(x) for x in reencs], str(rand)]
+				else:
-			self.assertEqual(commitments_right[i], EosObject.to_sha256(EosObject.to_json(val_json))[0])
 					verify_shuffle(perm, i, reencs)
 		
+		# NB: This isn't doing it in sequence, it's just testing a left mixnet and a right mixnet respectively
+		do_mixnet(0)
+		do_mixnet(1)
+
 class ElectionTestCase(EosTestCase):
+	@classmethod
+	def setUpClass(cls):
+		client.drop_database('test')
+	
 	def do_task_assert(self, election, task, next_task):
 		self.assertEqual(election.workflow.get_task(task).status, WorkflowTask.Status.READY)
 		if next_task is not None:
@@ -191,7 +197,7 @@ class ElectionTestCase(EosTestCase):
 			election.voters.append(voter)
 		
 		for i in range(3):
-			mixing_trustee = MixingTrustee(mix_order=i)
+			mixing_trustee = MixingTrustee()
 			election.mixing_trustees.append(mixing_trustee)
 		
 		election.sk = EGPrivateKey.generate()
@@ -225,7 +231,38 @@ class ElectionTestCase(EosTestCase):
 		election.save()
 		
 		# Close voting
-		self.do_task_assert(election, 'eos.base.workflow.TaskCloseVoting', 'eos.base.workflow.TaskDecryptVotes')
+		self.do_task_assert(election, 'eos.base.workflow.TaskCloseVoting', 'eos.psr.workflow.TaskMixVotes')
+		election.save()
+		
+		# Mix votes
+		election.workflow.get_task('eos.psr.workflow.TaskMixVotes').enter()
+		election.save()
+		
+		# Do the mix
+		for i in range(len(election.questions)):
+			for j in range(len(election.mixing_trustees)):
+				mixnet = RPCMixnet(j)
+				if j > 0:
+					orig_answers = election.mixing_trustees[j - 1].mixed_questions[i]
+				else:
+					orig_answers = []
+					for voter in election.voters:
+						for ballot in voter.ballots:
+							orig_answers.append(ballot.encrypted_answers[i])
+				shuffled_answers, commitments = mixnet.shuffle(orig_answers)
+				election.mixing_trustees[j].mixed_questions.append(EosList(shuffled_answers))
+				election.mixing_trustees[j].commitments.append(EosList(commitments))
+		
+		election.workflow.get_task('eos.psr.workflow.TaskMixVotes').exit()
+		election.save()
+		
+		# Verify mixes
+		election.workflow.get_task('eos.psr.workflow.TaskVerifyMixes').enter()
+		election.save()
+		
+		# TODO
+		
+		election.workflow.get_task('eos.psr.workflow.TaskVerifyMixes').exit()
 		election.save()
 		
 		# Decrypt votes, for realsies

eos/psr/workflow.py

@@ -16,10 +16,41 @@
 
 from eos.core.objects import *
 from eos.base.workflow import *
+import eos.base.workflow
 
 # Concrete tasks
 # ==============
 
+class TaskMixVotes(WorkflowTask):
+	depends_on = ['eos.base.workflow.TaskCloseVoting']
+	
+	def on_enter(self):
+		# Do not automatically exit this task
+		pass
+
+class TaskVerifyMixes(WorkflowTask):
+	depends_on = ['eos.psr.workflow.TaskMixVotes']
+	
+	def on_enter(self):
+		# Do not automatically exit this task
+		pass
+
+class TaskDecryptVotes(eos.base.workflow.TaskDecryptVotes):
+	depends_on = ['eos.psr.workflow.TaskVerifyMixes']
+	
+	def on_enter(self):
+		election = self.recurse_parents('eos.base.election.Election')
+		
+		for _ in range(len(election.questions)):
+			election.results.append(EosObject.objects['eos.base.election.RawResult']())
+		
+		for i in range(len(election.mixing_trustees[-1].mixed_questions)):
+			for encrypted_answer in election.mixing_trustees[-1].mixed_questions[i]:
+				answer = encrypted_answer.decrypt()
+				election.results[i].answers.append(answer)
+		
+		self.exit()
+
 # Concrete workflows
 # ==================
 
@@ -30,5 +61,7 @@ class PSRWorkflow(Workflow):
 		self.tasks.append(TaskConfigureElection())
 		self.tasks.append(TaskOpenVoting())
 		self.tasks.append(TaskCloseVoting())
-		self.tasks.append(TaskDecryptVotes())
+		self.tasks.append(TaskMixVotes())
+		self.tasks.append(TaskVerifyMixes())
+		self.tasks.append(TaskDecryptVotes()) # The PSR one, not the base one
 		self.tasks.append(TaskReleaseResults())