class MixedAnswers(HeliosModel):
mixnet = models.ForeignKey('ElectionMixnet', related_name='mixed_answers')
question = models.PositiveIntegerField(default=0)
mixed_answers = LDObjectField(type_hint='phoebus/MixedAnswers', null=True)
shuffling_proof = models.TextField(null=True)
class Meta:
unique_together = (('mixnet', 'question'))
class Voter(HeliosModel):
election = models.ForeignKey(Election)
# let's link directly to the user now
# FIXME: delete this as soon as migrations are set up
#name = models.CharField(max_length = 200, null=True)
#voter_type = models.CharField(max_length = 100)
#voter_id = models.CharField(max_length = 100)
uuid = models.CharField(max_length = 50)
# for users of type password, no user object is created
# but a dynamic user object is created automatically
user = models.ForeignKey('helios_auth.User', null=True)
# if user is null, then you need a voter login ID and password
voter_login_id = models.CharField(max_length = 100, null=True)
voter_password = models.CharField(max_length = 100, null=True)
voter_name = models.CharField(max_length = 200, null=True)
voter_email = models.CharField(max_length = 250, null=True)
# if election uses aliases
alias = models.CharField(max_length = 100, null=True)
# we keep a copy here for easy tallying
vote = LDObjectField(type_hint = 'legacy/EncryptedVote',
null=True)
vote_hash = models.CharField(max_length = 100, null=True)
cast_at = models.DateTimeField(auto_now_add=False, null=True)
class Meta:
unique_together = (('election', 'voter_login_id'))
app_label = 'helios'
def __init__(self, *args, **kwargs):
super(Voter, self).__init__(*args, **kwargs)
def get_user(self):
# stub the user so code is not full of IF statements
return self.user or User(user_type='password', user_id=self.voter_email, name=self.voter_name)
def __unicode__(self):
user = self.get_user()
return user.name
@classmethod
@transaction.atomic
def register_user_in_election(cls, user, election):
voter_uuid = str(uuid.uuid4())
voter = Voter(uuid= voter_uuid, user = user, election = election)
# do we need to generate an alias?
if election.use_voter_aliases:
heliosutils.lock_row(Election, election.id)
alias_num = election.last_alias_num + 1
voter.alias = "V%s" % alias_num
voter.save()
return voter
@classmethod
def get_by_election(cls, election, cast=None, order_by='voter_login_id', after=None, limit=None):
"""
FIXME: review this for non-GAE?
"""
query = cls.objects.filter(election = election)
# the boolean check is not stupid, this is ternary logic
# none means don't care if it's cast or not
if cast == True:
query = query.exclude(cast_at = None)
elif cast == False:
query = query.filter(cast_at = None)
# little trick to get around GAE limitation
# order by uuid only when no inequality has been added
if cast == None or order_by == 'cast_at' or order_by =='-cast_at':
query = query.order_by(order_by)
# if we want the list after a certain UUID, add the inequality here
if after:
if order_by[0] == '-':
field_name = "%s__gt" % order_by[1:]
else:
field_name = "%s__gt" % order_by
conditions = {field_name : after}
query = query.filter (**conditions)
if limit:
query = query[:limit]
return query
@classmethod
def get_all_by_election_in_chunks(cls, election, cast=None, chunk=100):
return cls.get_by_election(election)
@classmethod
def get_by_election_and_voter_id(cls, election, voter_id):
try:
return cls.objects.get(election = election, voter_login_id = voter_id)
except cls.DoesNotExist:
return None
@classmethod
def get_by_election_and_user(cls, election, user):
try:
return cls.objects.get(election = election, user = user)
except cls.DoesNotExist:
return None
@classmethod
def get_by_election_and_uuid(cls, election, uuid):
query = cls.objects.filter(election = election, uuid = uuid)
try:
return query[0]
except:
return None
@classmethod
def get_by_user(cls, user):
return cls.objects.select_related().filter(user = user).order_by('-cast_at')
@property
def datatype(self):
return self.election.datatype.replace('Election', 'Voter')
@property
def vote_tinyhash(self):
"""
get the tinyhash of the latest castvote
"""
if not self.vote_hash:
return None
return CastVote.objects.get(vote_hash = self.vote_hash).vote_tinyhash
@property
def election_uuid(self):
return self.election.uuid
@property
def name(self):
return self.get_user().name
@property
def voter_id(self):
return self.get_user().user_id
@property
def voter_id_hash(self):
if self.voter_login_id:
# for backwards compatibility with v3.0, and since it doesn't matter
# too much if we hash the email or the unique login ID here.
value_to_hash = self.voter_login_id
else:
value_to_hash = self.voter_id
try:
return utils.hash_b64(value_to_hash)
except:
try:
return utils.hash_b64(value_to_hash.encode('latin-1'))
except:
return utils.hash_b64(value_to_hash.encode('utf-8'))
@property
def voter_type(self):
return self.get_user().user_type
@property
def display_html_big(self):
return self.get_user().display_html_big
def send_message(self, subject, body):
self.get_user().send_message(subject, body)
def can_update_status(self):
return self.get_user().can_update_status()
def generate_password(self, length=10):
if self.voter_password:
raise Exception(_('password already exists'))
self.voter_password = heliosutils.random_string(length, alphabet='abcdefghjkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789')
# metadata for the election
@property
def metadata(self):
self.user = self.get_user()
return {
'voter_email': self.voter_email,
'uuid': self.uuid,
'voter_name': self.voter_name,
'vote_hash': self.vote_hash,
'cast_at': self.cast_at,
'alias': self.alias,
'user_id': self.user.user_id,
'election id': self.election.id,
'election name': self.election.name,
'election url': self.election.url
}
@property
def pretty_name(self):
if self.voter_name:
return self.voter_name
if self.voter_email:
return self.voter_email
if self.name:
return self.name
return self.voter_login_id
def store_vote(self, cast_vote):
# only store the vote if it's cast later than the current one
if self.cast_at and cast_vote.cast_at < self.cast_at:
return
self.vote = cast_vote.vote
self.vote_hash = cast_vote.vote_hash
self.cast_at = cast_vote.cast_at
self.save()
def last_cast_vote(self):
return CastVote(vote = self.vote, vote_hash = self.vote_hash, cast_at = self.cast_at, voter=self)
class Election(HeliosModel):
admin = models.ForeignKey(User)
uuid = models.CharField(max_length=50, null=False)
# keep track of the type and version of election, which will help dispatch to the right
# code, both for crypto and serialization
# v3 and prior have a datatype of "legacy/Election"
# v3.1 will still use legacy/Election
# later versions, at some point will upgrade to "2011/01/Election"
datatype = models.CharField(max_length=250, null=False, default="legacy/Election")
short_name = models.CharField(max_length=100, unique=True)
name = models.CharField(max_length=250)
ELECTION_TYPES = (
('election', _('Election')),
('referendum', _('Referendum'))
)
election_type = models.CharField(max_length=250, null=False, default='election', choices = ELECTION_TYPES)
private_p = models.BooleanField(default=False, null=False)
voto_unico = models.BooleanField(default=False, null=False)
description = models.TextField()
public_key = LDObjectField(type_hint = 'legacy/EGPublicKey',
null=True)
private_key = LDObjectField(type_hint = 'legacy/EGSecretKey',
null=True)
questions = LDObjectField(type_hint = 'legacy/Questions',
null=True)
# eligibility is a JSON field, which lists auth_systems and eligibility details for that auth_system, e.g.
# [{'auth_system': 'cas', 'constraint': [{'year': 'u12'}, {'year':'u13'}]}, {'auth_system' : 'password'}, {'auth_system' : 'openid', 'constraint': [{'host':'http://myopenid.com'}]}]
eligibility = LDObjectField(type_hint = 'legacy/Eligibility',
null=True)
# open registration?
# this is now used to indicate the state of registration,
# whether or not the election is frozen
openreg = models.BooleanField(default=False)
# featured election?
featured_p = models.BooleanField(default=False)
# voter aliases?
use_voter_aliases = models.BooleanField(default=False)
# auditing is not for everyone
use_advanced_audit_features = models.BooleanField(default=True, null=False)
# randomize candidate order?
randomize_answer_order = models.BooleanField(default=False, null=False)
# where votes should be cast
cast_url = models.CharField(max_length = 500)
# dates at which this was touched
created_at = models.DateTimeField(auto_now_add=True)
modified_at = models.DateTimeField(auto_now_add=True)
# dates at which things happen for the election
frozen_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
archived_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
# dates for the election steps, as scheduled
# these are always UTC
registration_starts_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
voting_starts_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
voting_ends_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
# if this is non-null, then a complaint period, where people can cast a quarantined ballot.
# we do NOT call this a "provisional" ballot, since provisional implies that the voter has not
# been qualified. We may eventually add this, but it can't be in the same CastVote table, which
# is tied to a voter.
complaint_period_ends_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
tallying_starts_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
# dates when things were forced to be performed
voting_started_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
voting_extended_until = models.DateTimeField(auto_now_add=False, default=None, null=True)
voting_ended_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
tallying_started_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
tallying_finished_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
tallies_combined_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
# we want to explicitly release results
result_released_at = models.DateTimeField(auto_now_add=False, default=None, null=True)
# the hash of all voters (stored for large numbers)
voters_hash = models.CharField(max_length=100, null=True)
# encrypted tally, each a JSON string
# used only for homomorphic tallies
encrypted_tally = LDObjectField(type_hint = 'legacy/Tally',
null=True)
# results of the election
result = LDObjectField(type_hint = 'legacy/Result',
null=True)
# decryption proof, a JSON object
# no longer needed since it's all trustees
result_proof = JSONField(null=True)
# help email
help_email = models.EmailField(null=True)
# downloadable election info
election_info_url = models.CharField(max_length=300, null=True)
class Meta:
app_label = 'helios'
def __unicode__(self):
return self.name
# metadata for the election
@property
def metadata(self):
return {
'help_email': self.help_email or settings.HELP_EMAIL_ADDRESS,
'private_p': self.private_p,
'voto_unico': self.voto_unico,
'use_advanced_audit_features': self.use_advanced_audit_features,
'randomize_answer_order': self.randomize_answer_order
}
@property
def pretty_type(self):
return dict(self.ELECTION_TYPES)[self.election_type]
@property
def num_cast_votes(self):
return self.voter_set.exclude(vote=None).count()
@property
def num_voters(self):
return self.voter_set.count()
@property
def num_trustees(self):
return self.trustee_set.count()
@property
def last_alias_num(self):
"""
FIXME: we should be tracking alias number, not the V* alias which then
makes things a lot harder
"""
if not self.use_voter_aliases:
return None
return heliosutils.one_val_raw_sql("select max(cast(substring(alias, 2) as integer)) from " + Voter._meta.db_table + " where election_id = %s", [self.id]) or 0
@property
def encrypted_tally_hash(self):
if not self.encrypted_tally:
return None
return utils.hash_b64(self.encrypted_tally.toJSON())
@property
def is_archived(self):
return self.archived_at != None
@property
def description_bleached(self):
return bleach.clean(self.description, tags = bleach.ALLOWED_TAGS + ['p', 'h4', 'h5', 'h3', 'h2', 'br', 'u'])
@classmethod
def get_featured(cls):
return cls.objects.filter(featured_p = True).order_by('short_name')
@classmethod
def get_or_create(cls, **kwargs):
return cls.objects.get_or_create(short_name = kwargs['short_name'], defaults=kwargs)
@classmethod
def get_by_user_as_admin(cls, user, archived_p=None, limit=None):
query = cls.objects.filter(admin = user)
if archived_p == True:
query = query.exclude(archived_at= None)
if archived_p == False:
query = query.filter(archived_at= None)
query = query.order_by('-created_at')
if limit:
return query[:limit]
else:
return query
@classmethod
def get_by_user_as_voter(cls, user, archived_p=None, limit=None):
query = cls.objects.filter(voter__user = user)
if archived_p == True:
query = query.exclude(archived_at= None)
if archived_p == False:
query = query.filter(archived_at= None)
query = query.order_by('-created_at')
if limit:
return query[:limit]
else:
return query
@classmethod
def get_by_uuid(cls, uuid):
try:
return cls.objects.select_related().get(uuid=uuid)
except cls.DoesNotExist:
return None
@classmethod
def get_by_short_name(cls, short_name):
try:
return cls.objects.get(short_name=short_name)
except cls.DoesNotExist:
return None
def save_questions_safely(self, questions):
"""
Because Django doesn't let us override properties in a Pythonic way... doing the brute-force thing.
"""
# verify all the answer_urls
for q in questions:
for answer_url in q['answer_urls']:
if not answer_url or answer_url == "":
continue
# abort saving if bad URL
if not (answer_url[:7] == "http://" or answer_url[:8]== "https://"):
return False
self.questions = questions
return True
def add_voters_file(self, uploaded_file):
"""
expects a django uploaded_file data structure, which has filename, content, size...
"""
# now we're just storing the content
# random_filename = str(uuid.uuid4())
# new_voter_file.voter_file.save(random_filename, uploaded_file)
new_voter_file = VoterFile(election = self, voter_file_content = uploaded_file.read())
new_voter_file.save()
self.append_log(ElectionLog.VOTER_FILE_ADDED)
return new_voter_file
def user_eligible_p(self, user):
"""
Checks if a user is eligible for this election.
"""
# registration closed, then eligibility doesn't come into play
if not self.openreg:
return False
if self.eligibility == None:
return True
# is the user eligible for one of these cases?
for eligibility_case in self.eligibility:
if user.is_eligible_for(eligibility_case):
return True
return False
def eligibility_constraint_for(self, user_type):
if not self.eligibility:
return []
# constraints that are relevant
relevant_constraints = [constraint['constraint'] for constraint in self.eligibility if constraint['auth_system'] == user_type and constraint.has_key('constraint')]
if len(relevant_constraints) > 0:
return relevant_constraints[0]
else:
return []
def eligibility_category_id(self, user_type):
"when eligibility is by category, this returns the category_id"
if not self.eligibility:
return None
constraint_for = self.eligibility_constraint_for(user_type)
if len(constraint_for) > 0:
constraint = constraint_for[0]
return AUTH_SYSTEMS[user_type].eligibility_category_id(constraint)
else:
return None
@property
def pretty_eligibility(self):
if not self.eligibility:
return _("Anyone can vote.")
else:
return_val = "<ul>"
for constraint in self.eligibility:
if constraint.has_key('constraint'):
for one_constraint in constraint['constraint']:
return_val += "<li>%s</li>" % AUTH_SYSTEMS[constraint['auth_system']].pretty_eligibility(one_constraint)
else:
return_val += "<li> any %s user</li>" % constraint['auth_system']
return_val += "</ul>"
return return_val
def voting_has_started(self):
"""
has voting begun? voting begins if the election is frozen, at the prescribed date or at the date that voting was forced to start
"""
return self.frozen_at != None and (self.voting_starts_at == None or (timezone.now() >= (self.voting_started_at or self.voting_starts_at)))
def voting_has_stopped(self):
"""
has voting stopped? if tally computed, yes, otherwise if we have passed the date voting was manually stopped at,
or failing that the date voting was extended until, or failing that the date voting is scheduled to end at.
"""
voting_end = self.voting_ended_at or self.voting_extended_until or self.voting_ends_at
return (voting_end != None and timezone.now() >= voting_end) or self.encrypted_tally
@property
def issues_before_freeze(self):
issues = []
if self.questions == None or len(self.questions) == 0:
issues.append(
{'type': 'questions',
'action': _("add questions to the ballot")}
)
trustees = Trustee.get_by_election(self)
if len(trustees) == 0:
issues.append({
'type': 'trustees',
'action': _("add at least one trustee")
})
for t in trustees:
if t.public_key == None:
issues.append({
'type': 'trustee keypairs',
'action': _('have trustee %(name)s generate a keypair') % {'name': t.name}
})
if self.voter_set.count() == 0 and not self.openreg:
issues.append({
"type" : "voters",
"action" : _("enter your voter list (or open registration to the public)")
})
return issues
def ready_for_tallying(self):
return timezone.now() >= self.tallying_starts_at
def compute_tally(self):
"""
tally the election, assuming votes already verified
"""
tally = self.init_tally()
for voter in self.voter_set.exclude(vote=None):
tally.add_vote(voter.vote, verify_p=False)
self.encrypted_tally = tally
self.save()
def ready_for_decryption(self):
return self.encrypted_tally != None
def ready_for_decryption_combination(self):
"""
do we have a tally from all trustees?
"""
for t in Trustee.get_by_election(self):
if not t.decryption_factors:
return False
return True
def release_result(self):
"""
release the result that should already be computed
"""
if not self.result:
return
self.result_released_at = timezone.now()
def combine_decryptions(self):
"""
combine all of the decryption results
"""
# gather the decryption factors
trustees = Trustee.get_by_election(self)
decryption_factors = [t.decryption_factors for t in trustees]
self.result = self.encrypted_tally.decrypt_from_factors(decryption_factors, self.public_key)
self.append_log(ElectionLog.DECRYPTIONS_COMBINED)
self.save()
def generate_voters_hash(self):
"""
look up the list of voters, make a big file, and hash it
"""
# FIXME: for now we don't generate this voters hash:
return
if self.openreg:
self.voters_hash = None
else:
voters = Voter.get_by_election(self)
voters_json = utils.to_json([v.toJSONDict() for v in voters])
self.voters_hash = utils.hash_b64(voters_json)
def increment_voters(self):
## FIXME
return 0
def increment_cast_votes(self):
## FIXME
return 0
def set_eligibility(self):
"""
if registration is closed and eligibility has not been
already set, then this call sets the eligibility criteria
based on the actual list of voters who are already there.
This helps ensure that the login box shows the proper options.
If registration is open but no voters have been added with password,
then that option is also canceled out to prevent confusion, since
those elections usually just use the existing login systems.
"""
# don't override existing eligibility
if self.eligibility != None:
return
# enable this ONLY once the cast_confirm screen makes sense
#if self.voter_set.count() == 0:
# return
auth_systems = copy.copy(settings.AUTH_ENABLED_AUTH_SYSTEMS)
voter_types = [r['user__user_type'] for r in self.voter_set.values('user__user_type').distinct() if r['user__user_type'] != None]
# password is now separate, not an explicit voter type
if self.voter_set.filter(user=None).count() > 0:
voter_types.append('password')
else:
# no password users, remove password from the possible auth systems
if 'password' in auth_systems:
auth_systems.remove('password')
# closed registration: limit the auth_systems to just the ones
# that have registered voters
if not self.openreg:
auth_systems = [vt for vt in voter_types if vt in auth_systems]
self.eligibility = [{'auth_system': auth_system} for auth_system in auth_systems]
self.save()
def freeze(self):
"""
election is frozen when the voter registration, questions, and trustees are finalized
"""
if len(self.issues_before_freeze) > 0:
raise Exception(_("cannot freeze an election that has issues"))
self.frozen_at = timezone.now()
# voters hash
self.generate_voters_hash()
self.set_eligibility()
# public key for trustees
trustees = Trustee.get_by_election(self)
combined_pk = trustees[0].public_key
for t in trustees[1:]:
combined_pk = combined_pk * t.public_key
self.public_key = combined_pk
# log it
self.append_log(ElectionLog.FROZEN)
self.save()
def generate_trustee(self, params):
"""
generate a trustee including the secret key,
thus a helios-based trustee
"""
# FIXME: generate the keypair
keypair = params.generate_keypair()
# create the trustee
trustee = Trustee(election = self)
trustee.uuid = str(uuid.uuid4())
trustee.name = settings.DEFAULT_FROM_NAME
trustee.email = settings.DEFAULT_FROM_EMAIL
trustee.public_key = keypair.pk
trustee.secret_key = keypair.sk
# FIXME: is this at the right level of abstraction?
trustee.public_key_hash = datatypes.LDObject.instantiate(trustee.public_key, datatype='legacy/EGPublicKey').hash
trustee.pok = trustee.secret_key.prove_sk(algs.DLog_challenge_generator)
trustee.save()
def get_helios_trustee(self):
trustees_with_sk = self.trustee_set.exclude(secret_key = None)
if len(trustees_with_sk) > 0:
return trustees_with_sk[0]
else:
return None
def has_helios_trustee(self):
return self.get_helios_trustee() != None
def helios_trustee_decrypt(self):
tally = self.encrypted_tally
tally.init_election(self)
trustee = self.get_helios_trustee()
factors, proof = tally.decryption_factors_and_proofs(trustee.secret_key)
trustee.decryption_factors = factors
trustee.decryption_proofs = proof
trustee.save()
def append_log(self, text):
item = ElectionLog(election = self, log=text, at=timezone.now())
item.save()
return item
def get_log(self):
return self.electionlog_set.order_by('-at')
@property
def url(self):
return helios.views.get_election_url(self)
def init_tally(self):
# FIXME: create the right kind of tally
from helios.workflows import homomorphic
return homomorphic.Tally(election=self)
@property
def registration_status_pretty(self):
if self.openreg:
return "Open"
else:
return "Closed"
@classmethod
def one_question_winner(cls, question, result, num_cast_votes):
"""
determining the winner for one question
"""
# sort the answers , keep track of the index
counts = sorted(enumerate(result), key=lambda(x): x[1])
counts.reverse()
the_max = question['max'] or 1
the_min = question['min'] or 0
# if there's a max > 1, we assume that the top MAX win
if the_max > 1:
return [c[0] for c in counts[:the_max]]
# if max = 1, then depends on absolute or relative
if question['result_type'] == 'absolute':
if counts[0][1] >= (num_cast_votes/2 + 1):
return [counts[0][0]]
else:
return []
else:
# assumes that anything non-absolute is relative
return [counts[0][0]]
@property
def winners(self):
"""
Depending on the type of each question, determine the winners
returns an array of winners for each question, aka an array of arrays.
assumes that if there is a max to the question, that's how many winners there are.
"""
return [self.one_question_winner(self.questions[i], self.result[i], self.num_cast_votes) for i in range(len(self.questions))]
@property
def pretty_result(self):
if not self.result:
return None
# get the winners
winners = self.winners
raw_result = self.result
prettified_result = []
# loop through questions
for i in range(len(self.questions)):
q = self.questions[i]
pretty_question = []
# go through answers
for j in range(len(q['answers'])):
a = q['answers'][j]
count = raw_result[i][j]
pretty_question.append({'answer': a, 'count': count, 'winner': (j in winners[i])})
prettified_result.append({'question': q['short_name'], 'answers': pretty_question})
return prettified_result
class Trustee(HeliosModel):
election = models.ForeignKey(Election)
uuid = models.CharField(max_length=50)
name = models.CharField(max_length=200)
email = models.EmailField()
secret = models.CharField(max_length=100)
# public key
public_key = LDObjectField(type_hint = 'legacy/EGPublicKey',
null=True)
public_key_hash = models.CharField(max_length=100)
# secret key
# if the secret key is present, this means
# Helios is playing the role of the trustee.
secret_key = LDObjectField(type_hint = 'legacy/EGSecretKey',
null=True)
# proof of knowledge of secret key
pok = LDObjectField(type_hint = 'legacy/DLogProof',
null=True)
# decryption factors
decryption_factors = LDObjectField(type_hint = datatypes.arrayOf(datatypes.arrayOf('core/BigInteger')),
null=True)
decryption_proofs = LDObjectField(type_hint = datatypes.arrayOf(datatypes.arrayOf('legacy/EGZKProof')),
null=True)
class Meta:
unique_together = (('election', 'email'))
app_label = 'helios'
def save(self, *args, **kwargs):
"""
override this just to get a hook
"""
# not saved yet?
if not self.secret:
self.secret = heliosutils.random_string(12)
self.election.append_log("Trustee %s added" % self.name)
super(Trustee, self).save(*args, **kwargs)
@classmethod
def get_by_election(cls, election):
return cls.objects.filter(election = election)
@classmethod
def get_by_uuid(cls, uuid):
return cls.objects.get(uuid = uuid)
@classmethod
def get_by_election_and_uuid(cls, election, uuid):
return cls.objects.get(election = election, uuid = uuid)
@classmethod
def get_by_election_and_email(cls, election, email):
try:
return cls.objects.get(election = election, email = email)
except cls.DoesNotExist:
return None
@property
def datatype(self):
return self.election.datatype.replace('Election', 'Trustee')
def verify_decryption_proofs(self):
"""
verify that the decryption proofs match the tally for the election
"""
# verify_decryption_proofs(self, decryption_factors, decryption_proofs, public_key, challenge_generator):
return self.election.encrypted_tally.verify_decryption_proofs(self.decryption_factors, self.decryption_proofs, self.public_key, algs.EG_fiatshamir_challenge_generator)
class CastVote(HeliosModel):
# the reference to the voter provides the voter_uuid
voter = models.ForeignKey(Voter)
# the actual encrypted vote
vote = LDObjectField(type_hint = 'legacy/EncryptedVote')
# cache the hash of the vote
vote_hash = models.CharField(max_length=100)
# a tiny version of the hash to enable short URLs
vote_tinyhash = models.CharField(max_length=50, null=True, unique=True)
cast_at = models.DateTimeField(auto_now_add=True)
# some ballots can be quarantined (this is not the same thing as provisional)
quarantined_p = models.BooleanField(default=False, null=False)
released_from_quarantine_at = models.DateTimeField(auto_now_add=False, null=True)
# when is the vote verified?
verified_at = models.DateTimeField(null=True)
invalidated_at = models.DateTimeField(null=True)
# auditing purposes, like too many votes from the same IP, if it isn't expected
cast_ip = models.GenericIPAddressField(null=True)
class Meta:
app_label = 'helios'
@property
def datatype(self):
return self.voter.datatype.replace('Voter', 'CastVote')
@property
def voter_uuid(self):
return self.voter.uuid
@property
def voter_hash(self):
return self.voter.hash
@property
def is_quarantined(self):
return self.quarantined_p and not self.released_from_quarantine_at
def set_tinyhash(self):
"""
find a tiny version of the hash for a URL slug.
"""
safe_hash = self.vote_hash
for c in ['/', '+']:
safe_hash = safe_hash.replace(c,'')
length = 8
while True:
vote_tinyhash = safe_hash[:length]
if CastVote.objects.filter(vote_tinyhash = vote_tinyhash).count() == 0:
break
length += 1
self.vote_tinyhash = vote_tinyhash
def save(self, *args, **kwargs):
"""
override this just to get a hook
"""
# not saved yet? then we generate a tiny hash
if not self.vote_tinyhash:
self.set_tinyhash()
super(CastVote, self).save(*args, **kwargs)
@classmethod
def get_by_voter(cls, voter):
return cls.objects.filter(voter = voter).order_by('-cast_at')
def verify_and_store(self):
# if it's quarantined, don't let this go through
if self.is_quarantined:
raise Exception(_("cast vote is quarantined, verification and storage is delayed."))
result = self.vote.verify(self.voter.election)
if result:
self.verified_at = timezone.now()
else:
self.invalidated_at = timezone.now()
# save and store the vote as the voter's last cast vote
self.save()
if result:
self.voter.store_vote(self)
return result
def issues(self, election):
"""
Look for consistency problems
"""
issues = []
# check the election
if self.vote.election_uuid != election.uuid:
issues.append(_("the vote's election UUID does not match the election for which this vote is being cast"))
return issues
class CastVote(HeliosModel):
# the reference to the voter provides the voter_uuid
voter = models.ForeignKey(Voter, models.CASCADE)
# the actual encrypted vote
vote = LDObjectField(type_hint = 'legacy/EncryptedVote')
# cache the hash of the vote
vote_hash = models.CharField(max_length=100)
# a tiny version of the hash to enable short URLs
vote_tinyhash = models.CharField(max_length=50, null=True, unique=True)
cast_at = models.DateTimeField(auto_now_add=True)
# some ballots can be quarantined (this is not the same thing as provisional)
quarantined_p = models.BooleanField(default=False, null=False)
released_from_quarantine_at = models.DateTimeField(auto_now_add=False, null=True)
# when is the vote verified?
verified_at = models.DateTimeField(null=True)
invalidated_at = models.DateTimeField(null=True)
# auditing purposes, like too many votes from the same IP, if it isn't expected
cast_ip = models.GenericIPAddressField(null=True)
# blockchain log
tx_hash = models.CharField(max_length=100, null=True)
@property
def datatype(self):
return self.voter.datatype.replace('Voter', 'CastVote')
@property
def voter_uuid(self):
return self.voter.uuid
@property
def voter_hash(self):
return self.voter.hash
@property
def voter_id_hash(self):
return self.voter.user_id_hash
@property
def is_quarantined(self):
return self.quarantined_p and not self.released_from_quarantine_at
def set_tinyhash(self):
"""
find a tiny version of the hash for a URL slug.
"""
safe_hash = self.vote_hash
for c in ['/', '+']:
safe_hash = safe_hash.replace(c,'')
length = 8
while True:
vote_tinyhash = safe_hash[:length]
if CastVote.objects.filter(vote_tinyhash = vote_tinyhash).count() == 0:
break
length += 1
self.vote_tinyhash = vote_tinyhash
def save(self, *args, **kwargs):
"""
override this just to get a hook
"""
# not saved yet? then we generate a tiny hash
if not self.vote_tinyhash:
self.set_tinyhash()
super(CastVote, self).save(*args, **kwargs)
@classmethod
def get_by_voter(cls, voter):
return cls.objects.filter(voter = voter).order_by('-cast_at')
def verify_and_store(self, election_contract_address, election_contract_abi, private_key):
# if it's quarantined, don't let this go through
if self.is_quarantined:
raise Exception("cast vote is quarantined, verification and storage is delayed.")
result = self.vote.verify(self.voter.election)
if result:
self.verified_at = datetime.datetime.utcnow() + datetime.timedelta(hours=3)
else:
self.invalidated_at = datetime.datetime.utcnow() + datetime.timedelta(hours=3)
try:
# send transaction with the vote valided
vote_hash_hex = heliosutils.get_vote_hash_hex(self.vote_hash)
election_contract = w3.eth.contract(address=election_contract_address, abi=election_contract_abi)
cast_at_int = int(self.cast_at.timestamp())
if result:
# TODO: Bug with verification time
verified_at_now = self.verified_at
verified_at_int = int(verified_at_now.timestamp())
if cast_at_int == verified_at_int:
verified_at_int += 1
else:
verified_at_int = 0
gas_estimate = election_contract.functions.vote(self.voter.user_id_hash,
vote_hash_hex,
cast_at_int,
verified_at_int) \
.estimateGas({'from': settings.SERVER_NODE_ADDRESS})
if gas_estimate < Web3.toWei('5', 'gwei'):
register_vote_txn = election_contract.functions.vote(self.voter.user_id_hash,
vote_hash_hex,
cast_at_int,
verified_at_int).buildTransaction(
{'nonce': w3.eth.getTransactionCount(settings.SERVER_NODE_ADDRESS),
'gasPrice': w3.eth.gasPrice,
'gas': gas_estimate})
private_key_bytes = bytes.fromhex(private_key)
signed_txn = w3.eth.account.sign_transaction(register_vote_txn, private_key=private_key_bytes)
signed_txn_hash = w3.eth.sendRawTransaction(signed_txn.rawTransaction)
receipt = w3.eth.waitForTransactionReceipt(signed_txn_hash)
self.tx_hash = signed_txn_hash.hex()
except Exception as e:
print(e)
raise Exception('Error during casting the vote on blockchain')
# save and store the vote as the voter's last cast vote
self.save()
if result:
self.voter.store_vote(self)
return result
def issues(self, election):
"""
Look for consistency problems
"""
issues = []
# check the election
if self.vote.election_uuid != election.uuid:
issues.append("the vote's election UUID does not match the election for which this vote is being cast")
return issues
