48 lines
1.6 KiB
Python
48 lines
1.6 KiB
Python
from Crypto.Util.number import *
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from math import lcm
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import random
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class pailier:
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def __init__(self):
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self.primes = [getPrime(512) for _ in range(2)]
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self.n = 1
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self.phi = 1
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self.mul = 1
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for i in range(2):
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self.n *= self.primes[i]
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self.phi *= (self.primes[i] - 1)
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self.n2 = self.n * self.n
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self.g = [pow(random.randrange(1, self.n2), self.primes[i], self.n2) for i in range(2)]
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for x in self.g:
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self.mul = (self.mul * x) % self.n2
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self.miu = inverse(self.L(pow(self.mul, self.phi, self.n2)), self.n)
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self.alpha = [None, None]
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for idx in range(2):
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while True:
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a = random.randrange(2, self.n - 1)
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if GCD(a, self.n) == 1:
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self.alpha[idx] = a
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break
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self.beta = [random.randrange(0, self.n), random.randrange(0, self.n)]
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def L(self, val):
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return (val - 1) // self.n
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def pubkey(self):
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return (self.n, self.g)
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def encrypt(self, msg: int) -> int:
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r = random.randrange(0, self.n - 1)
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gb = self.g[random.randrange(0, 2)]
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gm = pow(gb, msg, self.n2)
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rn = pow(r, self.n, self.n2)
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return (gm * rn) % self.n2
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def decrypt(self, ct: int) -> int:
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raw = self.L(pow(ct, self.phi, self.n2)) % self.n
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raw = (raw * self.miu) % self.n
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t = pow(ct % self.n, (self.n - 1) // 2, self.n) if (self.n % 2 == 1) else 0
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idx = 0 if t == 1 else 1
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return (self.alpha[idx] * raw + self.beta[idx]) % self.n
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