127 lines
3.2 KiB
Python
127 lines
3.2 KiB
Python
#!/usr/bin/env python3
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import os, sys, json, random, hashlib, hmac
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from Crypto.Cipher import AES
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from Crypto.Util.Padding import pad
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with open("/flag.txt", "rb") as f:
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flag = f.read()
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menu = (
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"1) encrypt\n"
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"2) profit\n"
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"3) nyerah\n"
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">> "
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)
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k = 1024
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n = 169
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rng = random.SystemRandom()
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def rand(k_bits: int) -> int:
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return rng.randrange(1, 1 << k_bits)
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def gen(n: int, k_bits: int):
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a = [rand(k_bits) for _ in range(n)]
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return a
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def b2b(b: bytes) -> list[int]:
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out = []
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for byte in b:
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for i in range(8):
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out.append((byte >> i) & 1)
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return out
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def pack(bits) -> bytes:
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out = bytearray()
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for i in range(0, len(bits), 8):
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chunk = bits[i:i+8]
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val = 0
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for j, bit in enumerate(chunk):
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val |= (bit & 1) << j
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out.append(val)
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return bytes(out)
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def gen_key(x_bits: list[int], saltx: bytes, salty: bytes, length: int = 16) -> bytes:
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material = pack(x_bits)
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prk = hashlib.pbkdf2_hmac("sha256", material, saltx, 131072, dklen=32)
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return hmac.new(prk, b"afk-players-wanted-now" + salty + b"\x01", hashlib.sha256).digest()[:length]
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def enc(k: bytes, data: bytes):
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iv = os.urandom(16)
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ct = AES.new(k, AES.MODE_CBC, iv).encrypt(pad(data, 16))
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return iv, ct
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def add(a, x_bits) -> int:
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return sum(ai for ai, xi in zip(a, x_bits) if xi)
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def main():
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a = gen(n, k)
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x_bits = b2b(flag)
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if len(x_bits) < n:
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x_bits += [rng.randrange(0, 2) for _ in range(n - len(x_bits))]
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else:
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x_bits = x_bits[:n]
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s = add(a, x_bits)
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saltx = os.urandom(16)
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salty = os.urandom(16)
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key = gen_key(x_bits, saltx, salty)
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iv, ct = enc(key, flag)
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header = {
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"n": n,
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"k_bits": k,
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}
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print(json.dumps(header, separators=(",", ":")), flush=True)
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while True:
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try:
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print(menu, end="", flush=True)
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line = sys.stdin.readline()
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if not line:
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break
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try:
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choice = int(line.strip())
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except ValueError:
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print("sheesh")
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continue
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if choice == 1:
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print("data: ", end="", flush=True)
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dline = sys.stdin.readline()
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if not dline:
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break
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try:
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data = bytes.fromhex(dline.strip())
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except Exception:
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print("hmmm")
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continue
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iv, ct = enc(key, data)
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print(iv.hex())
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print(ct.hex())
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elif choice == 2:
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print(json.dumps({"a": a}, separators=(",", ":")))
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print(str(s))
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print(saltx.hex())
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print(salty.hex())
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print(iv.hex())
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print(ct.hex())
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elif choice == 3:
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print("bubay")
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return
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else:
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print("tidak ada yang mustahil, hehehe")
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except Exception:
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print("zzz")
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if __name__ == "__main__":
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main()
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