34 lines
862 B
Python
34 lines
862 B
Python
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#!/usr/bin/env sage
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from Crypto.Util.number import *
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from random import *
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from flag import flag
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def keygen(nbit, l):
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p = getPrime(nbit)
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pubkey = []
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for _ in range(l):
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r, s = getPrime(nbit), getPrime(nbit >> 1)
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pubkey.append(r * p + s)
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return p, pubkey
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def encrypt(msg, pubkey, size, nbit):
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bmsg = bin(bytes_to_long(msg))[2:]
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ENC, ERR = [], [getRandomNBitInteger(nbit >> 2) for _ in range(len(pubkey))]
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I = [[getRandomRange(0, l) for _ in range(size)] for _ in range(len(bmsg))]
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J = I.copy()
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shuffle(J)
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for i in range(len(bmsg)):
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BSE = [pubkey[_] for _ in I[i]]
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NSE = [ERR[_] for _ in J[i]]
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ENC.append((p - 1337) * sum(BSE) + 31337 * sum(NSE) + int(bmsg[i]))
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return ENC
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nbit, l, size = 128, 19, 5
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p, pubkey = keygen(nbit, l)
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ENC = encrypt(flag, pubkey, size, nbit)
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print(f'p = SECRET')
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print(f'pubkey = CENSORED')
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print(f'ENC = {ENC}')
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