Chameleon is a polymorphic UDP tunneling protocol where each session deterministically derives a unique wire format ("genome") from a pre-shared key via HKDF-SHA256. The derived genome controls the magic byte, header field order, decoy fields, nonce size, length encoding, padding range, and wagon size range, yielding over 10¹3 possible wire formats. Traffic appears as pure noise with ~7. 9 bits/byte Shannon entropy. Authenticated encryption is provided by ChaCha20-Poly1305, XChaCha20-Poly1305, or AES-256-GCM with epoch-based nonces and a 256-epoch anti-replay sliding window. An optional stream mode emits a constant flow of genome-shaped "wagons" at a configurable rate envelope, carrying real data when available and random chaff otherwise. This defends against passive timing and activity inference on top of structural polymorphism - an observer cannot distinguish active browsing from idle. Per-packet wagon sizes are drawn from a genome-derived range so only a peer with the PSK knows the envelope. This paper describes the protocol architecture, genome derivation mechanism, cryptographic layer, reliable stream multiplexer (SACK, NewReno, flow control), stream-mode cover traffic, security analysis, and performance evaluation (30 Mbit/s direct, 86-97% throughput retention with stream mode at a 500 KB/s - 3 MB/s envelope; 67 concurrent streams; 7. 9 bits/byte wire entropy).
william-aqn (Thu,) studied this question.