Skip to content

Adding dynamic flagcheck and fraction of flag for cryptoversectf2023/lfsr #173

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
x-64 wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Adding dynamic flagcheck and fraction of flag for cryptoversectf2023/lfsr #173

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
2d5382a
Adding dynamic flagcheck and fraction of flag for cryptoversectf2023/…
x-64 Jan 31, 2026
22d5ffc
Merge branch 'main' into dynamic_flagcheck_and_fraction_of_flag_for_c…
x-64 Feb 9, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Binary file modified cryptoversectf2023/lsfr/flagCheck
View file
Open in desktop
Binary file not shown.
9 changes: 5 additions & 4 deletions cryptoversectf2023/lsfr/lfsr
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,15 +2,16 @@

from Crypto.Util.number import *
# from secret import flag
prefix = "pwn.college{"

with open('/flag', 'r') as file:
flag = file.read().strip()

# assert flag.startswith("cvctf{")
# assert flag.endswith("}")
assert flag.startswith(prefix)
assert flag.endswith("}")

flag = flag[6:-1].encode()
# assert len(flag) == 8
flag = flag[len(prefix):len(prefix)+8].encode()
assert len(flag) == 8

def explore(state, mask):
curr = (state << 1) & 0xffffffff
Expand Down