#!/usr/bin/env python3
import sys
from Crypto.Util.number import *
from flag import flag
def die(*args):
pr(*args)
quit()
def pr(*args):
s = " ".join(map(str, args))
sys.stdout.write(s + "\n")
sys.stdout.flush()
def sc():
return sys.stdin.buffer.readline()
def check_nr(a, p, q):
return pow(a, (p - 1) // 2, p) == p - 1 and pow(a, (q - 1) // 2, q) == q - 1
def gotam(nbit):
p, q = [getPrime(nbit) for _ in ':)']
n = p * q
while True:
t = getRandomRange(1, n - 1)
if check_nr(t, p, q):
break
return (n, t), (p, q)
def encrypt(msg, pubkey):
n, t = pubkey
M = bin(bytes_to_long(msg))[2:].zfill(1 << 10)
l = len(M)
E = [
t ** int(M[_]) * getRandomNBitInteger(n.bit_length() - 1) ** 2 % n
for _ in range(l)
]
return E
def main():
border = "┃"
pr(
"┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓"
)
pr(
border,
"Unlock Gotam's tailored encryption—can you outsmart this custom asymmetric enigma?",
border,
)
pr(
"┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛"
)
pubkey, privkey = gotam(128)
del privkey
while True:
pr(
f"{border} Options: \n{border}\t[E]ncrypt flag \n{border}\t[P]ublic data \n{border}\t[Q]uit"
)
ans = sc().decode().strip().lower()
if ans == "e":
enc = encrypt(flag, pubkey)
for e in enc:
pr(border, f"{hex(e) = }")
elif ans == "p":
pr(border, "n, t = ", ", ".join(map(hex, pubkey)))
elif ans == "q":
die(border, "Quitting...")
else:
die(border, "Bye...")
if __name__ == "__main__":
main()