yip is a VPN — its whole job is security — but it is pre-1.0 software with one maintainer and no external audit. Treat it accordingly. If you rely on it in a threat-model where compromise is dangerous, read the honest accounting below first.

Report privately via GitHub's private vulnerability reporting, or email the maintainer at the address in the repo profile. Include enough to reproduce (affected version/commit, config, and a description or PoC). We'll acknowledge, work a fix, and credit you unless you'd rather stay anonymous. There is no bounty program.

Fixes land on main and are tagged for release.

• Confidentiality + integrity: ChaCha20-Poly1305 AEAD over a Noise-IK session, per-direction keys, a sliding replay window, and ~120 s forward-secret rekeys.
• Post-Quantum Security Margin: Single-RTT hybrid key exchange pairing NIST FIPS 203 ML-KEM-512 (Kyber) with classical X25519 Diffie-Hellman to defeat Harvest-Now, Decrypt-Later (HNDL) attacks.
• Decentralized Root Authority: Optional RFC 9591 FROST(Ed25519, SHA-512) threshold CA with ROAST asynchronous coordination, preprocessed 1-RTT nonces, and memory-locked (mlock) rollback-immune nonce vaults to eliminate single-point-of-compromise root key theft.
• Identity & Admission: Mesh membership requires CA-signed certificates; handshake admission checks static keys; TAI64N monotonic timestamps prevent replay and endpoint-hijacking; endpoint roaming follows only authenticated packets; and rendezvous registration is cryptographically authenticated.
• Traffic Analysis Defense (DAITA): Discrete packet-length bucketing, stochastic multi-packet cover traffic bursts during idle periods, and bounded egress micro-jitter delay queues prevent statistical flow analysis.
• Content-DPI Resistance: No fixed wire bytes or constant offsets; verified clean against a 4-engine DPI oracle panel (nDPI, tshark, Suricata, Zeek); an Xray-REALITY transport mimics real Chrome TLS 1.3 for hostile networks and splices unauthorized probers to authentic decoy servers.

• Physical Peer IP Concealment: yip is a peer-to-peer overlay network, not an anonymizing mix-net like Tor. Connected nodes authenticate directly and see each other's physical IP addresses.
• No independent commercial audit: The implementation uses audited cryptographic primitives (ring, snow, frost-ed25519), but the full protocol composition and daemon have not yet undergone an external third-party commercial audit.

If a documented limitation above matters to your threat model, that's a reason to plan accordingly — but a new way to break the stated guarantees is exactly what we want to hear about privately.