トランプのカードを配るときに不正をなくすみたいなやつ
https://link.springer.com/content/pdf/10.1007%2F3-540-39799-X_10.pdf
Coppersmith1986_Chapter_CheatingAtMentalPoker.pdf
Protocol A
from Crypto.Util.number import getPrime, inverse from math import gcd import random p = getPrime(512) while True: a = random.randint(2, p-1) # Alice's secret if gcd(a, p-1) == 1: break while True: b = random.randint(2, p-1) # Bob's secret if gcd(b, p-1) == 1: break ainv = inverse(a, p-1) binv = inverse(b, p-1) cards = [2+i for i in range(52)] # Alice encrypts cards cards = [pow(c, a, p) for c in cards] # Alice sends cards to Bob # Bob choices alice's hand and Bob's hand hands = random.sample(cards, k=10) alice_hand, bob_hand = hands[:5], hands[5:] # Bob encrypts bob_hand bob_hand = [pow(c, b, p) for c in bob_hand] # Bob sends alice_hand and bob_hand to alice # Alice decrypts both hands alice_hand = [pow(c, ainv, p) for c in alice_hand] bob_hand = [pow(c, ainv, p) for c in bob_hand] # Alice sends bob_hand to Bob # Bob decrypt his hand bob_hand = [pow(c, binv, p) for c in bob_hand] print(alice_hand) print(bob_hand)
