Eos/eos/base/election.py

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# Eos - Verifiable elections
# Copyright © 2017 RunasSudo (Yingtong Li)
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# 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.objects import *
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from eos.core.bigint import *
from eos.base.workflow import *
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class Answer(EmbeddedObject):
pass
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class EncryptedAnswer(EmbeddedObject):
pass
class NullEncryptedAnswer(EncryptedAnswer):
answer = EmbeddedObjectField()
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def decrypt(self):
return None, self.answer
class Ballot(EmbeddedObject):
#_id = UUIDField()
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encrypted_answers = EmbeddedObjectListField()
election_id = UUIDField()
election_hash = StringField()
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answers = EmbeddedObjectListField(is_hashed=False) # Used for ballots to be audited
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def deaudit(self):
encrypted_answers_deaudit = EosList()
for encrypted_answer in self.encrypted_answers:
encrypted_answers_deaudit.append(encrypted_answer.deaudit())
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return Ballot(encrypted_answers=encrypted_answers_deaudit, election_id=self.election_id, election_hash=self.election_hash)
class Vote(TopLevelObject):
_ver = StringField(default='0.6')
_id = UUIDField()
voter_id = UUIDField()
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ballot = EmbeddedObjectField()
cast_at = DateTimeField()
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comment = StringField()
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cast_ip = StringField(is_protected=True)
cast_fingerprint = BlobField(is_protected=True)
class Voter(EmbeddedObject):
_ver = StringField(default='0.6')
_id = UUIDField()
votes = RelatedObjectListField(related_type=Vote, object_type=None, this_field='_id', related_field='voter_id')
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class User(EmbeddedObject):
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admins = []
def matched_by(self, other):
return self == other
def is_admin(self):
for admin in User.admins:
if admin.matched_by(self):
return True
return False
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def generate_password():
if is_python:
#__pragma__('skip')
import random
return ''.join(random.SystemRandom().choices('23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz', k=12))
#__pragma__('noskip')
else:
return None
class EmailUser(User):
name = StringField()
email = StringField(is_protected=True)
password = StringField(is_protected=True, default=generate_password)
def matched_by(self, other):
if not isinstance(other, EmailUser):
return False
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return self.email.lower() == other.email.lower() and self.password == other.password
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class UserVoter(Voter):
user = EmbeddedObjectField()
@property
def name(self):
return self.user.name
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class Question(EmbeddedObject):
prompt = StringField()
class Result(EmbeddedObject):
pass
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class ListChoiceQuestion(Question):
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_ver = StringField(default='0.5')
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choices = EmbeddedObjectListField()
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min_choices = IntField()
max_choices = IntField()
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randomise_choices = BooleanField(default=False)
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def pretty_answer(self, answer):
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if len(answer.choices) == 0:
return '(blank votes)'
flat_choices = self.flatten_choices()
return ', '.join([flat_choices[choice].name for choice in answer.choices])
def max_bits(self):
answer = self.answer_type(choices=list(range(self.max_choices)))
return len(EosObject.to_json(EosObject.serialise_and_wrap(answer))) * 8
def flatten_choices(self):
# Return a flat list of Choices, without Tickets
flat_choices = []
for choice in self.choices:
if isinstance(choice, Ticket):
for choice2 in choice.choices:
flat_choices.append(choice2)
else:
flat_choices.append(choice)
return flat_choices
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def randomised_choices(self):
if not self.randomise_choices:
return self.choices
else:
# Clone list
output = EosList([x for x in self.choices])
# Fisher-Yates shuffle
i = len(output)
while i != 0:
rnd = BigInt.noncrypto_random(0, i - 1)
rnd = rnd.__int__()
i -= 1
output[rnd], output[i] = output[i], output[rnd]
return output
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class ApprovalAnswer(Answer):
choices = ListField(IntField())
class ApprovalQuestion(ListChoiceQuestion):
answer_type = ApprovalAnswer
class PreferentialAnswer(Answer):
choices = ListField(IntField())
class PreferentialQuestion(ListChoiceQuestion):
answer_type = PreferentialAnswer
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class Choice(EmbeddedObject):
name = StringField()
party = StringField(default=None)
@property
def party_or_ticket(self):
if self.party is not None:
return self.party
else:
ticket = self.recurse_parents(Ticket)
if ticket:
return ticket.name
return None
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class Ticket(EmbeddedObject):
name = StringField()
choices = EmbeddedObjectListField()
class RawResult(Result):
plaintexts = ListField(EmbeddedObjectListField())
answers = EmbeddedObjectListField()
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def count(self):
combined = []
for answer in self.answers:
index = next((i for i, val in enumerate(combined) if val[0] == answer), None)
if index is None:
combined.append([answer, 1])
else:
combined[index][1] += 1
combined.sort(key=lambda x: x[1], reverse=True)
return combined
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class MultipleResult(Result):
results = EmbeddedObjectListField()
class STVResult(Result):
elected = ListField(IntField())
log = StringField()
random = BlobField()
class Election(TopLevelObject):
_id = UUIDField()
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workflow = EmbeddedObjectField(Workflow) # Once saved, we don't care what kind of workflow it is
name = StringField()
kind = StringField(default='election')
voters = EmbeddedObjectListField(is_hashed=False)
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questions = EmbeddedObjectListField()
results = EmbeddedObjectListField(is_hashed=False)
def verify(self):
#__pragma__('skip')
from eos.core.hashing import SHA256
#__pragma__('noskip')
election_hash = SHA256().update_obj(self).hash_as_b64()
for voter in self.voters:
for vote in voter.votes.get_all():
if vote.ballot.election_id != self._id:
raise Exception('Invalid election ID on ballot')
if vote.ballot.election_hash != election_hash:
raise Exception('Invalid election hash on ballot')