Security posture

• Client-side AES-256-GCM — files are encrypted on the originating machine before leaving it. Per-file random IVs.
• Per-pair key material — keys are derived per machine pair via ECDH and never sent to the coordinator.
• Zero-knowledge coordinator — the VPS only handles routing, presence, generation metadata, and short-lived ciphertext blobs.
• TLS 1.3 with post-quantum hybrid key exchange where the client supports it; HSTS preload, OCSP must-staple.
• JWT auth via Google OAuth, verified with jwks-rsa; tokens are short-lived and rotated.
• Strict CSP, COOP, COEP, CORP, Permissions-Policy on the coordinator dashboard.
• SPF / DKIM / DMARC p=reject on outbound mail, MTA-STS enforced.
• Reproducible builds for the VS Code extension; signed releases on GitHub.