All Writeups

Comprehensive collection of CTF challenges, solutions, and insights.


Filter by tag:

Raptor Weekly 2 - ECHELON Crypto 2 - 3.2 ; FREQUENCY

Recognizing a GCM nonce reuse vulnerability across two calibration reports, cancelling the keystream by XORing the ciphertexts, and recovering the anomaly report plaintext using a legacy diagnostic endpoint left running after decommission.

DEADROP Crypto 4 - DSA Again?

Two DSA signatures from the same key share an identical r value, a dead giveaway of nonce reuse. Recover the private key, forge a signature over the target authorization message, and submit it to the server.