101 lines
2.4 KiB
Python
101 lines
2.4 KiB
Python
from __future__ import annotations
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import hashlib
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import itertools
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import random
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import secrets
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from typing import List
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from week1 import BloodType
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def sha256(b: bytes) -> bytes:
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return hashlib.sha256(b).digest()
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def rand_bytes():
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return secrets.SystemRandom().getrandbits(128).to_bytes(16, "big")
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def xor_bytes(a: bytes, b: bytes, k=256) -> bytes:
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return (int.from_bytes(a, "big") ^ int.from_bytes(b, "big")).to_bytes(k, "big")
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class Gate:
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def __init__(self, left: Gate, right: Gate, index: int) -> None:
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self.left = left
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self.right = right
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self.i = index
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self.k = {
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0: rand_bytes(),
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1: rand_bytes()
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}
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self.output = None
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c_prime = {}
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for a, b in itertools.product((0, 1), repeat=2):
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c_prime[(a, b)] = xor_bytes(
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sha256(self.left.k[a] + self.right.k[b] + self.i.to_bytes(1, "big")),
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self.k[not a * b] + bytes(128 // 8)
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)
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pi = list(itertools.product((0, 1), repeat=2))
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random.shuffle(pi)
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self.c = {i: c_prime[p]
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for i, p in enumerate(pi)}
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class InputWire:
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def __init__(self, index) -> None:
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self.i = index
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self.k = {
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0: rand_bytes(),
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1: rand_bytes()
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}
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self.output = None
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class Circuit:
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def __init__(self, input_wires: List[InputWire], gates: List[Gate]) -> None:
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self.input_wires = input_wires
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self.gates = gates
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def evaluate(self, x: List[bytes]) -> bytes:
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for i, xi in enumerate(x):
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self.input_wires[i].output = xi
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for gate in self.gates:
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for j in range(4):
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xor = xor_bytes(
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sha256(gate.left.output + gate.right.output + gate.i),
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gate.c[j]
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)
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k_prime, tau = xor[:16], xor[16:]
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if tau == bytes(16):
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gate.output = k_prime
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return self.gates[-1].output
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def encode(e: List[InputWire], x: List[int]) -> List[bytes]:
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return [e[i].k[xi]
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for i, xi in enumerate(x)]
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class Alice:
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pass
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class Bob:
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pass
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def run(donor: BloodType, recipient: BloodType):
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m1 = Alice.choose(x)
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m2 = Bob.transfer(y, m2)
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z = Alice.retrieve(m2)
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return z
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def main():
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run(donor=BloodType.A_NEGATIVE, recipient=BloodType.B_POSITIVE)
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