import os
from Crypto.Cipher import AES
from Crypto.Hash import SHA256
from Crypto.Util.Padding import pad

FLAG = b"crypto{?????????????????????????????????????}"

# Base field
ea, eb = 110, 67
p = 2**ea*3**eb - 1
F.<i> = GF(p**2, modulus=[1,0,1])

# Public curve
E0 = EllipticCurve(F, [1,0])

# Torsion points
P2 = E0(118242575052254473701407051403380184157502700009529430046122822477*i + 57638278144985143549644316704182130279784191379170896458696787312, 80915735815367072410310689908590367651933218830435520913424043510*i + 35228327576503752484578273317308597612913304063200715424014549037)
Q2 = E0(27856673727210297071672501895829918842041821446996051944738115273*i + 101349537690838191347553037323956940169953967852439843389873653018, 45955772915614774101614751673022340983778200451506382887743008335*i + 76499786039494489791183573966490259392789635716963920208794989512)
P3 = E0(68702305424425607424554396971378391833152415806389206440833676844*i + 63162905189208938201083385603424075109355856156240516441321158383, 14452401602439328239712793251073780692192036710425129093829067649*i + 110903430163815016394569999096524527007769669322432532390635606190)
Q3 = E0(50967992419888058158544483269655763559879646024537212566396940681*i + 39165103284419354968504615023980382940222714919046676966425620242, 113476160032430656302485251779124302915433268423829474022852380544*i + 74814862075401178218909769629701747112662266906635780085603780902)

# Secret Keys
sA = 225902606209514408534212339057054
sB = 38410379124791756271891302485727

# TODO
def gen_public_key():
    pass

# TODO
def gen_shared_secret():
    pass

# TODO
shared_secret = gen_shared_secret()

def encrypt_flag(shared_secret):
    key = SHA256.new(data=str(shared_secret).encode()).digest()[:128]
    iv = os.urandom(16)
    cipher = AES.new(key, AES.MODE_CBC, iv)
    ct = cipher.encrypt(pad(FLAG, 16))

    return iv.hex(), ct.hex()

print(encrypt_flag(shared_secret))
# ('05a4cfbce59acb952128af83c9694390', '755b72b2e3bef2e7a4b2ce4a370f287ad04c1359bace25f3def8be23c0c49e89b4302408ad2dcb02d4875fe58c543d91')