83 lines
2.9 KiB
Python
83 lines
2.9 KiB
Python
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# Eos - Verifiable elections
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# Copyright © 2017 RunasSudo (Yingtong Li)
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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from eos.core.bigint import *
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from eos.core.objects import *
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from eos.psr.election import *
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class RPCMixnet:
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def __init__(self):
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self.params = []
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def random_permutation(self, n):
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permutation = list(range(n))
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# Fisher-Yates shuffle
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i = n
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while i != 0:
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rnd = BigInt.crypto_random(0, i - 1)
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rnd = rnd.__int__()
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i -= 1
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permutation[rnd], permutation[i] = permutation[i], permutation[rnd]
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return permutation
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def shuffle(self, encrypted_answers):
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shuffled_answers = [None] * len(encrypted_answers)
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permutations = self.random_permutation(len(encrypted_answers))
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permutations_and_reenc = []
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for i in range(len(encrypted_answers)):
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encrypted_answer = encrypted_answers[i]
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# Reencrypt the answer
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shuffled_blocks = []
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block_reencryptions = []
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for block in encrypted_answer.blocks:
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block2, reenc = block.reencrypt()
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shuffled_blocks.append(block2)
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block_reencryptions.append(reenc)
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# And shuffle it to the new position
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shuffled_answers[permutations[i]] = BlockEncryptedAnswer(blocks=shuffled_blocks)
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# Record the parameters
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permutations_and_reenc.append([permutations[i], block_reencryptions, block.public_key.group.random_element(), block.public_key.group.random_element()])
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commitments_left = []
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for i in range(len(permutations_and_reenc)):
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val = permutations_and_reenc[i]
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val_json = [val[0], [str(x) for x in val[1]], str(val[2])]
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commitments_left.append(EosObject.to_sha256(EosObject.to_json(val_json))[0])
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commitments_right = []
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for i in range(len(permutations_and_reenc)):
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# Find the answer that went to 'i'
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idx = next(idx for idx in range(len(permutations_and_reenc)) if permutations_and_reenc[idx][0] == i)
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val = permutations_and_reenc[idx]
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val_json = [idx, [str(x) for x in val[1]], str(val[3])]
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commitments_right.append(EosObject.to_sha256(EosObject.to_json(val_json))[0])
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self.params = permutations_and_reenc
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return shuffled_answers, commitments_left, commitments_right
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def challenge(self, i, is_left):
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if is_left:
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val = self.params[i]
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return [val[0], val[1], val[2]]
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else:
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idx = next(idx for idx in range(len(self.params)) if self.params[idx][0] == i)
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val = self.params[idx]
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return [idx, val[1], val[3]]
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