competition-stego-medialisted

# Competition Stego Media Use this skill only as a downstream specialization after `$ctf-sandbox-orchestrator` is already active and has established sandbox assumptions, node ownership, and evidence priorities. If that has not happened yet, return to `$ctf-sandbox-orchestrator` first. Use this skill when the challenge lives inside a media container, hidden channel, or appended payload rather than a conventional crypto blob. Reply in Simplified Chinese unless the user explicitly requests English. ## Quick Start 1. Confirm the real container type, dimensions, duration, codec, and chunk layout before guessing a hidden layer. 2. Check metadata, thumbnails, sidecar files, and appended trailers before deeper signal-domain work. 3. Rank candidate channels by evidence: alpha, palette, LSB, transform-domain residue, frame order, or container slack. 4. Preserve each extracted layer separately so the transform chain stays reproducible. 5. Stop when the hidden payload is reproduced, not merely suspected. ## Workflow ### 1. Establish Container Truth - Inspect headers, chunk tables, EXIF or document metadata, container indexes, thumbnails, and file size anomalies. - Compare declared format against observed structure to catch polyglots, appended archives, or malformed trailers. - Record exact offsets, frame numbers, or channel boundaries that look promising. ### 2. Inspect Candidate Channels - Check alpha, palette order, RGB or YUV planes, LSBs, spectrogram features, document obje