27 lines
783 B
Python
27 lines
783 B
Python
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#!/usr/bin/env python3
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from Crypto.Util.number import *
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from secret import PUBKEYS, flag
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def keygen(nbit, k): # Public key generation function
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while True:
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p, q = [2 ** k * getRandomNBitInteger(nbit - k) + 1 for _ in '01']
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if isPrime(p) and isPrime(q):
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while True:
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y = getRandomRange(2, p * q)
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if pow(y, (p - 1) // 2, p) == p - 1 and pow(y, (q - 1) // 2, q) == q - 1:
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pubkey = k, p * q, y
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return pubkey
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def encrypt(pubkey, m):
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k, n, y = pubkey
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assert k >= len(bin(m)[2:])
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x = getRandomRange(2, n)
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return pow(y, m, n) * pow(x, 2 ** k, n) % n
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flag = flag.lstrip(b'CCTF{').rstrip(b'}')
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flag = [bytes_to_long(flag[i*8:i*8 + 8]) for i in range(4)]
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print(f'PUBKEYS = {PUBKEYS}')
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ENC = [encrypt(PUBKEYS[_], flag[_]) for _ in range(4)]
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print(f'ENC = {ENC}')
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