solve.py

from Crypto.Cipher import AES
from Crypto.Util.number import *
from hashlib import md5

p = 108159532265181242371960862176089900437183046655107822712736597793129430067645352619047923366465213553080964155205008757015024406041606723580700542617009651237415277095236385696694741342539811786180063943404300498027896890240121098409649537982185247548732754713793214557909539077228488668731016501718242238229
A = 60804426023059829529243916100868813693528686280274100232668009387292986893221484159514697867975996653561494260686110180269479231384753818873838897508257692444056934156009244570713404772622837916262561177765724587140931364577707149626116683828625211736898598854127868638686640564102372517526588283709560663960
ciphertext = '9fb749ef7467a5aff04ec5c751e7dceca4f3386987f252a2fc14a8970ff097a81fcb1a8fbe173465eecb74fb1a843383'

s = (A) * pow(1 + A, -1, p) % p


def decrypt(c: bytes, key: int) -> bytes:
    iv = c[:16]
    ciphertext = c[16:]
    key = long_to_bytes(key)
    key = md5(key).digest()
    cipher = AES.new(key, AES.MODE_CBC, iv=iv)
    decrypted = cipher.decrypt(ciphertext)
    return decrypted


m = decrypt(bytes.fromhex(ciphertext), s)

print(m)