def test_publish(self) -> None:
# Arrange
now = datetime.now(timezone.utc)
manifest = Manifest("", ElectionType.unknown, now, now, [], [], [], [], [], [])
context = make_ciphertext_election_context(
1, 1, ONE_MOD_P, ONE_MOD_Q, ONE_MOD_Q
)
constants = ElectionConstants()
devices = []
guardian_records = [GuardianRecord("", "", ONE_MOD_Q, [], [])]
encrypted_ballots = []
spoiled_ballots = []
plaintext_tally = PlaintextTally("", [])
ciphertext_tally = CiphertextTally("", manifest, context)
# Act
publish(
manifest,
context,
constants,
devices,
encrypted_ballots,
spoiled_ballots,
ciphertext_tally.publish(),
plaintext_tally,
guardian_records,
)
# Assert
self.assertTrue(path.exists(RESULTS_DIR))
# Cleanup
rmtree(RESULTS_DIR)
def test_publish(self) -> None:
# Arrange
now = datetime.now(timezone.utc)
description = ElectionDescription(
"", ElectionType.unknown, now, now, [], [], [], [], [], []
)
context = CiphertextElectionContext(1, 1, ONE_MOD_P, ONE_MOD_Q)
constants = ElectionConstants()
devices = []
coefficients = [CoefficientValidationSet("", [], [])]
encrypted_ballots = []
tally = PlaintextTally("", [], [])
# Act
publish(
description,
context,
constants,
devices,
encrypted_ballots,
CiphertextTally("", description, context),
tally,
coefficients,
)
# Assert
self.assertTrue(path.exists(RESULTS_DIR))
# Cleanup
rmtree(RESULTS_DIR)
def start_tally(
request: StartTallyRequest = Body(...),
scheduler: Scheduler = Depends(get_scheduler),
) -> Any:
"""
Start a new tally of a collection of ballots
"""
ballots, description, context = _parse_tally_request(request)
tally = CiphertextTally("election-results", description, context)
return _tally_ballots(tally, ballots, scheduler)
def _tally_ballots(
tally: CiphertextTally,
ballots: List[CiphertextAcceptedBallot],
scheduler: Scheduler,
) -> Any:
"""
Append a series of ballots to a new or existing tally
"""
tally_succeeded = tally.batch_append(ballots, scheduler)
if tally_succeeded:
published_tally = publish_ciphertext_tally(tally)
return published_tally.to_json_object()
raise HTTPException(status_code=500, detail="Unable to tally ballots")
def process_message(
self,
message_type: Literal["tally.cast"],
message: Content,
context: TrusteeContext,
) -> Tuple[List[Content], ElectionStep[TrusteeContext]]:
contests: Dict[CONTEST_ID, CiphertextDecryptionContest] = {}
tally_cast: Dict[CONTEST_ID, CiphertextTallyContest] = deserialize(
message["content"], Dict[CONTEST_ID, CiphertextTallyContest])
# save for when compensating
context.tally = CiphertextTally("election-results",
context.election_metadata,
context.election_context)
context.tally.contests = tally_cast
for contest in tally_cast.values():
selections: Dict[
SELECTION_ID, CiphertextDecryptionSelection] = dict(
pair_with_object_id(
unwrap(
compute_decryption_share_for_selection(
context.guardian._election_keys,
selection,
context.election_context,
)))
for (_, selection) in contest.selections.items())
contests[contest.object_id] = CiphertextDecryptionContest(
contest.object_id,
context.guardian_id,
contest.description_hash,
selections,
)
tally_share = DecryptionShare(
context.tally.object_id,
guardian_id=context.guardian_id,
public_key=context.guardian.share_election_public_key().key,
contests=contests,
)
return [{
"message_type": "tally.trustee_share",
"content": serialize(tally_share)
}], ProcessEndTally()
def process_message(
self,
message_type: Literal["vote.cast", "end_vote"],
message: Union[Content, dict],
context: BulletinBoardContext,
) -> Union[NoReturn, Tuple[List[Content], Optional[ElectionStep]]]:
if message_type == "end_vote":
context.tally = CiphertextTally("election-results",
context.election_metadata,
context.election_context)
return [], ProcessStartTally()
ballot = deserialize(message["content"], CiphertextBallot)
if not ballot_is_valid_for_election(ballot, context.election_metadata,
context.election_context):
raise InvalidBallot()
else:
return [], None
def _cannot_erroneously_mutate_state(
self,
tally: CiphertextTally,
ballot: SubmittedBallot,
state_to_test: BallotBoxState,
) -> bool:
input_state = ballot.state
ballot.state = state_to_test
# remove the first selection
first_contest = ballot.contests[0]
first_selection = first_contest.ballot_selections[0]
ballot.contests[0].ballot_selections.remove(first_selection)
self.assertIsNone(tally_ballot(ballot, tally))
self.assertFalse(tally.append(ballot))
# Verify accumulation fails if the selection count does not match
if ballot.state == BallotBoxState.CAST:
first_tally = tally.contests[first_contest.object_id]
self.assertFalse(
first_tally.accumulate_contest(
ballot.contests[0].ballot_selections))
# pylint: disable=protected-access
_key, bad_accumulation = first_tally._accumulate_selections(
first_selection.object_id,
first_tally.selections[first_selection.object_id],
ballot.contests[0].ballot_selections,
)
self.assertIsNone(bad_accumulation)
ballot.contests[0].ballot_selections.insert(0, first_selection)
# modify the contest description hash
first_contest_hash = ballot.contests[0].description_hash
ballot.contests[0].description_hash = ONE_MOD_Q
self.assertIsNone(tally_ballot(ballot, tally))
self.assertFalse(tally.append(ballot))
ballot.contests[0].description_hash = first_contest_hash
# modify a contest object id
first_contest_object_id = ballot.contests[0].object_id
ballot.contests[0].object_id = "a-bad-object-id"
self.assertIsNone(tally_ballot(ballot, tally))
self.assertFalse(tally.append(ballot))
ballot.contests[0].object_id = first_contest_object_id
# modify a selection object id
first_contest_selection_object_id = (
ballot.contests[0].ballot_selections[0].object_id)
ballot.contests[0].ballot_selections[
0].object_id = "another-bad-object-id"
self.assertIsNone(tally_ballot(ballot, tally))
self.assertFalse(tally.append(ballot))
# Verify accumulation fails if the selection object id does not match
if ballot.state == BallotBoxState.CAST:
self.assertFalse(tally.contests[
ballot.contests[0].object_id].accumulate_contest(
ballot.contests[0].ballot_selections))
ballot.contests[0].ballot_selections[
0].object_id = first_contest_selection_object_id
# modify the ballot's hash
first_ballot_hash = ballot.manifest_hash
ballot.manifest_hash = ONE_MOD_Q
self.assertIsNone(tally_ballot(ballot, tally))
self.assertFalse(tally.append(ballot))
ballot.manifest_hash = first_ballot_hash
ballot.state = input_state
return True
def test_tally_ballot_invalid_input_fails(
self, everything: ELECTIONS_AND_BALLOTS_TUPLE_TYPE):
# Arrange
(
_election_description,
internal_manifest,
ballots,
_secret_key,
context,
) = everything
# encrypt each ballot
store = DataStore()
encryption_seed = ElectionFactory.get_encryption_device().get_hash()
for ballot in ballots:
encrypted_ballot = encrypt_ballot(ballot, internal_manifest,
context, encryption_seed)
encryption_seed = encrypted_ballot.code
self.assertIsNotNone(encrypted_ballot)
# add to the ballot store
store.set(
encrypted_ballot.object_id,
from_ciphertext_ballot(encrypted_ballot, BallotBoxState.CAST),
)
tally = CiphertextTally("my-tally", internal_manifest, context)
# act
cached_ballots = store.all()
first_ballot = cached_ballots[0]
first_ballot.state = BallotBoxState.UNKNOWN
# verify an UNKNOWN state ballot fails
self.assertIsNone(tally_ballot(first_ballot, tally))
self.assertFalse(tally.append(first_ballot))
# cast a ballot
first_ballot.state = BallotBoxState.CAST
self.assertTrue(tally.append(first_ballot))
# try to append a spoiled ballot
first_ballot.state = BallotBoxState.SPOILED
self.assertFalse(tally.append(first_ballot))
# Verify accumulation fails if the selection collection is empty
if first_ballot.state == BallotBoxState.CAST:
self.assertFalse(
tally.contests[first_ballot.object_id].accumulate_contest([]))
# pylint: disable=protected-access
# pop the cast ballot
tally._cast_ballot_ids.pop()
# reset to cast
first_ballot.state = BallotBoxState.CAST
self.assertTrue(
self._cannot_erroneously_mutate_state(tally, first_ballot,
BallotBoxState.CAST))
self.assertTrue(
self._cannot_erroneously_mutate_state(tally, first_ballot,
BallotBoxState.SPOILED))
self.assertTrue(
self._cannot_erroneously_mutate_state(tally, first_ballot,
BallotBoxState.UNKNOWN))
# verify a cast ballot cannot be added twice
first_ballot.state = BallotBoxState.CAST
self.assertTrue(tally.append(first_ballot))
self.assertFalse(tally.append(first_ballot))
# verify an already submitted ballot cannot be changed or readded
first_ballot.state = BallotBoxState.SPOILED
self.assertFalse(tally.append(first_ballot))
def test_tally_ballot_invalid_input_fails(
self, everything: ELECTIONS_AND_BALLOTS_TUPLE_TYPE):
# Arrange
metadata, ballots, secret_key, context = everything
# encrypt each ballot
store = BallotStore()
seed_hash = EncryptionDevice("Location").get_hash()
for ballot in ballots:
encrypted_ballot = encrypt_ballot(ballot, metadata, context,
seed_hash)
seed_hash = encrypted_ballot.tracking_hash
self.assertIsNotNone(encrypted_ballot)
# add to the ballot store
store.set(
encrypted_ballot.object_id,
from_ciphertext_ballot(encrypted_ballot, BallotBoxState.CAST),
)
subject = CiphertextTally("my-tally", metadata, context)
# act
cached_ballots = store.all()
first_ballot = cached_ballots[0]
first_ballot.state = BallotBoxState.UNKNOWN
# verify an UNKNOWN state ballot fails
self.assertIsNone(tally_ballot(first_ballot, subject))
self.assertFalse(subject.append(first_ballot))
# cast a ballot
first_ballot.state = BallotBoxState.CAST
self.assertTrue(subject.append(first_ballot))
# try to append a spoiled ballot
first_ballot.state = BallotBoxState.SPOILED
self.assertFalse(subject.append(first_ballot))
# Verify accumulation fails if the selection collection is empty
if first_ballot.state == BallotBoxState.CAST:
self.assertFalse(
subject.cast[first_ballot.object_id].elgamal_accumulate([]))
# pop the cast ballot
subject._cast_ballot_ids.pop()
# reset to cast
first_ballot.state = BallotBoxState.CAST
self.assertTrue(
self._cannot_erroneously_mutate_state(subject, first_ballot,
BallotBoxState.CAST))
self.assertTrue(
self._cannot_erroneously_mutate_state(subject, first_ballot,
BallotBoxState.SPOILED))
self.assertTrue(
self._cannot_erroneously_mutate_state(subject, first_ballot,
BallotBoxState.UNKNOWN))
# verify a spoiled ballot cannot be added twice
first_ballot.state = BallotBoxState.SPOILED
self.assertTrue(subject.append(first_ballot))
self.assertFalse(subject.append(first_ballot))
# verify an already spoiled ballot cannot be cast
first_ballot.state = BallotBoxState.CAST
self.assertFalse(subject.append(first_ballot))
# pop the spoiled ballot
subject.spoiled_ballots.pop(first_ballot.object_id)
# verify a cast ballot cannot be added twice
first_ballot.state = BallotBoxState.CAST
self.assertTrue(subject.append(first_ballot))
self.assertFalse(subject.append(first_ballot))
# verify an already cast ballot cannot be spoiled
first_ballot.state = BallotBoxState.SPOILED
self.assertFalse(subject.append(first_ballot))
def close_ballot_box(self):
self.context.tally = CiphertextTally('election-results',
self.context.election_metadata,
self.context.election_context)
self.step = ProcessTrusteeShare()
