Residue class enumeration given partial information of either end.
- pip
pip install enumer- Clone the repo
git clone https://github.com/Cosmic-Excalibur/enumer.gitenumer. Perform naive enumerations of representatives.tail_enumer. With the last few bits specified. This is done by simple modular arithmetic.head_tail_enumer. With both the last and first few bits specified. This is done by meet-in-the-middle tricks.
from secret import secret_message_from_someone
from enumer import *
# E
secret_message = secret_message_from_someone.encode('utf-8')
assert secret_message.startswith(b'Merry Christmas~~~~~~~~~~~~~~~~~~~~')
assert secret_message.endswith(b'padoru padoru!!!!!!!!!!!!!!!!!!!!!!!')
assert len(secret_message) == 191
flag = b2l(secret_message)
mod = int('1337133713371337133713371337133713371337133713371337'
'1337133713371337133713371337133713371337133713371337'
'1337133713371337133713371337133713371337133713371337'
'1337133713371337133713371337133713371337133713371337'
'1337133713371337133713371337133713371337133713371337'
'13371337133713371337133713371337133713371337000', 16)
ct = flag % mod
# ct = 0xfcad5e7f12e0fd8a5e8038e0fea85e80031e5e7f06e0fc9a5e7f29
# e0fd865e7f01e0fca89be0fca25e7f08e0fcbd5e7f2ae0fd875e80
# 0d1e5e810ce0fe875e8126e0fe8f5e8104e0fea89b45dc70e366ed
# 629b70ea6fe476ea1de65ef562e96c9b76ea72e9669b71ee72e666
# e866e35eed5f3fd20de055822dd862875ed34cce60f11a9d1a9d1a
# 9d1a9d1a9d1a9d1a9d1a9d1a9d1a3ebd0121
# D
head = b'Merry Christmas~~~~~~~~~~~~~~~~~~~~'
tail = b'padoru padoru!!!!!!!!!!!!!!!!!!!!!!!'
length = 191
for pt in head_tail_enumer(ct, mod, head, tail, length, size_limit = 15000):
if pt == flag:
print(l2b(pt).decode('utf-8'))For more examples, refer to enumer/test.
from enumer import run_enumer_tests
run_enumer_tests()- Merry Xmas 🎄🧑🎄
Merry Ymas 🎄🧑🎄Merry Zmas 🎄🧑🎄