帮我写一个paillier同态加密的python代码

好的，以下是一个简单的Paillier同态加密的Python代码：

import random
import math

class Paillier:
    def __init__(self, key_size):
        self.key_size = key_size
        self.public_key, self.private_key = self.generate_key_pair()

    def generate_key_pair(self):
        p, q = self.generate_primes()
        n = p * q
        phi_n = (p - 1) * (q - 1)
        g = n + 1
        l = self.l_function(g, n)
        mu = self.mod_inverse(l, n)
        public_key = (n, g)
        private_key = (p, q, mu)
        return public_key, private_key

    def generate_primes(self):
        p = random.randint(2**(self.key_size-1), 2**self.key_size-1)
        q = random.randint(2**(self.key_size-1), 2**self.key_size-1)
        while not self.is_prime(p) or not self.is_prime(q):
            p = random.randint(2**(self.key_size-1), 2**self.key_size-1)
            q = random.randint(2**(self.key_size-1), 2**self.key_size-1)
        return p, q

    def is_prime(self, n):
        if n <= 1:
            return False
        elif n <= 3:
            return True
        elif n % 2 == 0 or n % 3 == 0:
            return False
        i = 5
        while i * i <= n:
            if n % i == 0 or n % (i + 2) == 0:
                return False
            i += 6
        return True

    def l_function(self, x, n):
        return (x - 1) // n

    def mod_inverse(self, a, m):
        gcd, x, y = self.extended_gcd(a, m)
        if gcd != 1:
            return None
        else:
            return x % m

    def extended_gcd(self, a, b):
        if a == 0:
            return (b, 0, 1)
        else:
            gcd, x, y = self.extended_gcd(b % a, a)
            return (gcd, y - (b // a) * x, x)

    def encrypt(self, m):
        n, g = self.public_key
        r = random.randint(1, n)
        c = (pow(g, m, n**2) * pow(r, n, n**2)) % (n**2)
        return c

    def decrypt(self, c):
        p, q, mu = self.private_key
        n = p * q
        l = self.l_function(pow(c, p-1, p**2), p) * mu % p
        m = (pow(c, n, n**2) - 1) // n * l % n
        return m

示例代码中包含了Paillier加密方案的加密、解密、密钥生成等操作，你可以根据自己的需要进行调整和使用。