codelock

Four locks.
Each opens for correct code.

Write a solution in the editor and run it. Your code executes against a battery of test cases right here in your browser — when every case is correct, the lock decrypts and hands you a flag. Submit each flag in CTFd.

session flags captured: 0 / 4

Code runs locally in a sandboxed worker — nothing is uploaded. The flag is XOR-encrypted with a key derived from your output, so it only appears when your solution is genuinely correct.