LYKNCTF 2026 Forensics Writeup: 4 Challenges Solved (PNG Metadata XOR, Red-Channel LSB, JPEG-as-PNG ZIP Append, TRON USDT OFAC Trace)
LYKNCTF 2026’s forensics track is small but well-shaped: four challenges that cover the whole spectrum of file-format triage, from PNG chunk parsing and repeating-key XOR through steganographic LSB extraction and polyglot ZIP appending to a real on-chain USDT trace on TRON that ends at an OFAC-sanctioned wallet before landing in a Bitget hot wallet. Each challenge deliberately ships a decoy layer (an EXIF cover story, an IEND trailer with a fake “password hint,” a .png extension that lies about the container format, a suggestive first hop) that looks like the answer if you stop reading too early. ...