RSA算法Python代码

RSA算法是一种非对称加密算法，它需要一对密钥，一个用于加密，一个用于解密。以下是Python中实现RSA算法的代码：

import random
from math import gcd

def generate_keypair(p: int, q: int) -> tuple:
    n = p * q
    phi = (p - 1) * (q - 1)
    e = random.randrange(1, phi)
    g = gcd(e, phi)
    while g != 1:
        e = random.randrange(1, phi)
        g = gcd(e, phi)
    d = mod_inverse(e, phi)
    return ((e, n), (d, n))

def mod_inverse(a: int, m: int) -> int:
    m0 = m
    y = 0
    x = 1
    if m == 1:
        return 0
    while a > 1:
        q = a // m
        t = m
        m = a % m
        a = t
        t = y
        y = x - q * y
        x = t
    if x < 0:
        x = x + m0
    return x

def encrypt(pk: tuple, plaintext: str) -> list:
    key, n = pk
    cipher = [pow(ord(char), key, n) for char in plaintext]
    return cipher

def decrypt(pk: tuple, ciphertext: list) -> str:
    key, n = pk
    plain = [chr(pow(char, key, n)) for char in ciphertext]
    return ''.join(plain)

这里的 `generate_keypair` 函数生成了一对公钥和私钥， `encrypt` 函数用公钥加密明文， `decrypt` 函数用私钥解密密文。