> Source: https://nexusatlas.dev/security — Nexus Atlas developer documentation (Security). Converted from the HTML page; the page is canonical.

# Security posture

This page is the honest scorecard: what ships today in v0.2, what is on the roadmap, and the line between them drawn clearly — because a security page that blurs that line is itself a security finding. Deep-dive documents behind each row are available under [approved access](https://nexusatlas.dev/request-access).

## Cryptography

The data plane runs the **Noise IK** handshake pattern with X25519 key agreement, ChaCha20-Poly1305 AEAD and BLAKE2s hashing — a modern, formally analyzed construction (Dowling & Rösler 2018; Noise Explorer, IEEE EuroS&P 2019) in the same family as widely deployed commercial VPN protocols. Node identities are static Curve25519 keys; private keys live in zeroizing memory and rekeying is make-before-break. Release signing is Sigstore keyless — short-lived certificates tied to the CI workflow's identity — so there is *no long-term release-signing private key* to protect or leak.

**What we do not claim:** no FIPS 140-3 validation, no CSfC listing, no CNSA 2.0 compliance exists today. A validated cipher backend and a hybrid post-quantum handshake are roadmap items — documented as such, with the migration plan available under approved access. Any vendor telling you otherwise about comparable products deserves the same scrutiny.

## At a glance — v0.2

| Axis | Status |
|------|--------|
| Memory-safe core language (Rust) throughout the daemon | shipped |
| SBOM (CycloneDX) published with every release | shipped |
| Signed releases — Sigstore/cosign keyless + SLSA L3 provenance | shipped |
| Dependency gate in CI: advisories, yanked versions, license allowlist — re-scanned weekly | shipped |
| Hardened systemd unit (unprivileged user, one capability, syscall allowlist) | shipped |
| SELinux policy module and AppArmor profile | shipped |
| Ansible role deployable onto a STIG-baseline host | shipped |
| Peer-reviewed data-plane cryptography (Noise IK / X25519 / ChaCha20-Poly1305) | shipped |
| FIPS 140-3 validated cipher backend | roadmap |
| Hybrid post-quantum handshake (X25519 + ML-KEM) | roadmap |
| CSfC components-list submission | roadmap |
| Reproducible builds · VEX statements | roadmap |

The compliance framing to take from this table: the shipped artifacts are *designed to satisfy* the software-supply-chain expectations of EO 14028-era procurement (SBOMs, signed provenance, dependency auditing) — that is a design statement, not a certification claim.

## Security properties of the architecture itself

- **No phone-home by default.** The daemon works fully offline; console enrolment is an explicit operator action; crash reports stay local until an operator sends one, redacted, with an anonymous mode that strips identity.

- **Fail closed, everywhere it matters.** Unknown peers are rejected by default; every [auth-provider](https://nexusatlas.dev/guides/auth) failure mode denies; a misconfigured trust setup refuses to start rather than starting open.

- **Least privilege as packaging, not advice.** The shipped unit runs an unprivileged user with a single capability inside a syscall-filtered sandbox — [verifiable on your own host](https://nexusatlas.dev/guides/systemd) in one command.

- **Honest observability boundaries.** Support bundles and uploaded diagnostics are redacted by allowlist; private keys and mesh secrets cannot leave the node through any built-in path.

- **Know your crypto boundary.** Multi-hop mesh forwarding is hop-by-hop encrypted — a relay node you operate can read what it forwards, and the [documentation says so in bold](https://nexusatlas.dev/docs/concepts/mesh#crypto-boundary) instead of hoping you don't ask. Traversal relay *servers*, by contrast, forward opaque envelopes they cannot read.

## Verify, don't trust

Every release ships checksums, keyless signatures, SLSA L3 provenance and per-crate SBOMs — and the [verification recipe is public](https://nexusatlas.dev/security/verify), runnable by any auditor with a Linux box in about a minute. We publish the recipe precisely so that "how do we know this binary is yours?" is a command, not a meeting.

## The deep-dive set approved access

- [CNSA 2.0 transition plan](https://nexusatlas.dev/security/cnsa) — the migration path to a post-quantum-ready data plane, mapped against published deadlines.

- [CSfC inner-layer positioning](https://nexusatlas.dev/security/csfc) — how Atlas composes as the inner layer of a two-layer architecture.

- [OS hardening profile](https://nexusatlas.dev/security/hardening) — the confinement stack directive by directive, with live-system verification.

## Vulnerability disclosure

Security research is welcome. The canonical disclosure policy for the whole site family lives at [nexusatlas.io/security](https://nexusatlas.io/security#disclosure), and every Nexus Atlas host — this one included — serves `/.well-known/security.txt` pointing at it.