Everything the release needs except the version number, which stays at 0.5.0-dev until the tag. The changelog entry covers only the work that is new on this line. The point release's forty-six entries arrived under their own heading with the forward merge and are left alone; the twenty that remained are regrouped by topic and eight more added for changes no entry covered. Three of those eight matter to someone upgrading. Five root modules and four re-exports left the public library surface and Node::connections narrowed, none of it recorded anywhere; the entry names what to use instead and distinguishes the removed connection-phase enum from the Noise type of the same name, which is a different type that still exists. Tracing targets moved, so an existing RUST_LOG filter stops matching rather than erroring. And the handshake resend interval key no longer governs the first resend, which is now a constant, though it still governs later ones. Seven more entries cover the work that landed after the first content pass was written: the experimental native datagram API, the fipsctl probe diagnostic, per-instance transport addressing, the app-owned UDP socket seam, and the connect, disconnect and path-MTU fixes. The four bug fixes among them all reach the deployed line, so the release notes no longer claim this release carries exactly one fix for a shipped bug; it carries four. There is no security section, because after the split every security entry belongs to the point release. The release notes say so plainly rather than leaving a reader upgrading across both releases to conclude this one carries no security work. The notes are organized by audience, since the release spans OpenWrt routers, embedders, FreeBSD, and the existing platforms, and a single list serves none of them. The native datagram API is given a section of its own rather than folded into the embedding seam: it is a client-facing API rather than a way to host a node, and its one rule with no Berkeley-socket counterpart, that the v1 wire carries no half-close, needs to be somewhere a client author will read it. FreeBSD is advertised as supported on x86_64 only, stated wherever the platform appears. Android is advertised as an embedding seam and not as a supported platform: a compile-gated library surface with no artifact and no host application guide. The configuration table rename is carried through every shipped file that taught the old spelling: nine documentation files, the OpenWrt sample config and a test generator, twenty-two sites in all. Guides written this same cycle were among them, which is how the omission was found. The documentation that arrived with the native API was checked for the same omission and was already clean. The compatibility tests keep the old spelling deliberately, since they exist to test the fold. The changelog section is the fold of master's [Unreleased], not a snapshot of it. An earlier version of this commit took a copy that then drifted, so each section ended up holding a bullet the other did not and re-folding them would have picked a winner silently. Both causes were fixed on master instead — the NixOS module had never been recorded there, and the pre-release batch of fixes was new — so [Unreleased] is a strict superset and this is a copy rather than a merge. [0.5.0] carries all forty-six bullets byte for byte, [Unreleased] is empty, and [0.4.2] is untouched, checked by hashing it against master's copy. The BLE work landed after the content pass and gets one summary entry in the changelog and one section in the release notes rather than nine bullets: the ble_available gate replacing target_os = "linux", packet-boundary recovery for stream-oriented backends, peer recognition by node identity instead of a rotating link address, the L2CAP PSM moving into the backend seam and onto the advertisement, the embedder-supplied Android radio, bounded probe retry, and inbound handshakes moved off the accept loop. The two release-notes copies no longer share their link paths. Relative links resolve from one directory only, so the seven written for docs/releases/ all 404ed from the root copy. The root copy now uses paths from the repository root and the versioned copy keeps the ../ form; both sets were resolved against the tree. The same two links are broken the same way in the v0.4.0 through v0.4.2 notes, left as shipped history. The contributor tallies are re-derived against maint..HEAD rather than adjusted: twenty commits from outside the project and 171 from me, with Arjen at fifteen and fr34aky at two. An earlier count of twelve and 138 was carried from a measurement taken three days before this content was written, and the BLE branch widened the gap after it. Arjen's NixOS flake module, the UDP sin6_scope_id fix and most of the BLE rework were uncredited, as was fr34aky's L2CAP PSM seam. They want one last re-derive at tag time if anything lands before the tag. A sweep of all 99 tracked markdown files against the tree corrected fifty-three of them. Four told the reader to run a build.sh that does not exist; the only harness builder is testing/scripts/build.sh. The BLE build prerequisites were described as optional on the strength of a probe that build.rs does not perform, and bluez was named a build prerequisite when libdbus-sys asks only for libdbus-1-dev and pkg-config and bluez is the runtime daemon. Link cost is the primary sort key in next-hop ranking, not reserved for future use; Ethernet runs on macOS as well as Linux; the BLE MTU is the L2CAP CoC MTU rather than a negotiated ATT_MTU; effective Ethernet MTU is 1497; the LAN discovery subsystem is src/mdns and eight citations still named a src/discovery that never existed here. The connectivity states in three tutorials were invented, and their jq filters matched nothing including healthy peers. One command filtered on a literal fd97: address prefix, which only the first byte of fixes, so it returned empty for all but one reader in 256 and every later step using the variable failed silently. transports.tor.advertise_on_nostr was undocumented despite being validated against node.rendezvous.nostr.enabled. The transport design document gains the BLE section it never had, written from the source: the backend cascade and its compile_error tripwire, the platform gate, the PSM advertisement wire layout and the byte budget that forces a 16-bit service-data key, and the probe and admission bounds. Three source files carried the same class of staleness and are corrected with the documentation: the OpenWrt ipk usage line and Makefile error text both named a packaging/openwrt that does not exist, and chaos.sh parsed --subnet without listing it. Folded in with the content commit, having been prepared alongside it: The three GitHub Action pins that had gone stale. Every third-party action is pinned to a commit SHA, nothing reports that a pin has aged, and re-resolving all ten against their tags found dorny/test-reporter@v2, taiki-e/install-action@v2 and vmactions/freebsd-vm@v1 had moved. The three install-action@nextest references stay unpinned, since that action reads the tool to install from the ref name. check-action-pins.sh passes at 75 references and all nine workflow files parse. The lockfile refresh, which is the mutating half of the dependency sweep. Thirty-six packages move to their latest semver-compatible versions and every one is transitive; nothing declared in Cargo.toml changes version. No advisory forces any of them. It was taken before the validation battery, because a gate run against a lockfile that later moves proves nothing about what ships. The sha2 0.10 to 0.11, hkdf 0.12 to 0.13 and bech32 0.11 to 0.12 majors, three of the four deferred at v0.4.0 for change surface rather than security. All three land with no source change. sha2 and hkdf must move together, since both depend on digest 0.11, and neither changes an algorithm. That matters because the chaining-key KDF in the Noise handshake is built on Hkdf::<Sha256>, where an output change would be a wire break rather than a compile error; no known-answer vectors exist for that path, so the wire-compatibility gate is what covers it. secp256k1 0.31 is deliberately absent, since nostr's own requirement would leave two copies of the ECC library in the tree. The README support matrix, rebuilt as one feature table broken out by Linux variety. A single Linux column hid that Debian, Ubuntu, Arch and NixOS are one glibc build differing in packaging, that OpenWrt is musl and drops BLE, and that Android is not a daemon platform. Transport rows sort by how many platforms carry them. A Native API row reads its platform set from the cfg gates. The installer row becomes a package format row naming the artifact, and only the .deb is exercised per release. Four changelog and release-note gaps the BLE re-walk found: a Bluetooth LE bullet stranded inside the released 0.4.2 section, a missing Fixed entry for the scan and probe loop counting a pool-refused connection as an established link, the unnamed embedder call that installs an application-owned radio, and the fact that stopping the transport now stops scanning as well as advertising. Three release-document gaps found walking the unsurveyed commits: the UDP reuse-flag fix stated in the direction opposite to the one it was made, with the silent second-daemon bind it prevents left unsaid; the corrected native-API socket paragraph carried into both release-note copies, which still named SOCK_SEQPACKET on FreeBSD and two kernels where three are handled; and the coordinate-cache hardening, which shipped with no text anywhere despite adding four operator-visible status fields. That last entry states plainly that the checks are mitigations and not a closure, since the coordinate is still not authenticated. Also folded in, the documentation pass that followed the content commit: A stage-pipeline diagram for the probe, embedded in the fipsctl reference under the five-stage list. It draws the five stages left to right with each stage's failure reasons below it, and the bypass that skips both lookup stages when the coordinates are cached or the target is a direct peer. Its branches come from the probe state machine rather than from the report, so the path stage is drawn as the one failure that does not stop the probe. A rewrite of the README's "What FIPS does" section. It now opens with what a machine running FIPS gets, rather than with the two deployment modes, and gives the self-organizing and permissionless property its own paragraph since it holds for both modes. A regrouping of the README's feature list into the mesh, getting traffic onto it, and running a node, with a bullet added for the native datagram API, which had none despite sitting in the support matrix. The Quick start now leads with the released packages rather than a source build. It also fixes a real defect: the package enables fips.service and fips-dns.service and starts neither on a fresh install, so .fips name resolution was silently dead until the next reboot and neither page said to start the service. A rewrite of the release notes. They opened with seven subsections of upgrade caveats and reached the first feature two hundred lines in; they now open with a summary of the release and elaborate below it in the same order. Android is stated as supported through an embedded crate rather than as a standalone daemon, consistently across all three documents. The OpenWrt pair is corrected: it is 802.11s between routers with FIPS supplying encryption, authentication and routing, plus a convention of an open !FIPS SSID a client joins over WiFi, not meshing over a router's own radios. The probe's path output is described as the least-common-ancestor walk, which is the worst-case fallback route rather than the route a packet takes. Detail that did not change what a reader does was cut from the notes and kept in the changelog.
8.7 KiB
FIPS over a Mixnet — Single-Container Demo (Nym)
An isolated environment demonstrating how FIPS peer traffic can travel through a mixnet — a network that hides traffic patterns by routing each packet through several relays with cover traffic and timing obfuscation. The mixnet here is Nym, but the FIPS side is transport-agnostic: it just sees a SOCKS5 proxy, so any mixnet exposing one would slot in the same way.
Everything runs in one Docker container: the FIPS daemon, the mixnet
proxy (nym-socks5-client), a strfry
Nostr relay behind nginx, and dnsmasq.
┌────────────────────────── one container ───────────────────────────┐
│ │
│ nginx :80 ──► strfry :7777 (Nostr relay, fips0-only) │
│ │
│ fips daemon ── transports.nym ──► nym-socks5-client :1080 │
│ │ │ │
│ ▼ ▼ Sphinx packets │
│ fips0 (TUN, fd00::/8) Nym gateway ► 3 mix hops ► │
│ network requester ► peer (TCP) │
│ │
│ iptables: direct route to the peer is DROPped — the FIPS link │
│ can only exist through the mixnet. │
└────────────────────────────────────────────────────────────────────┘
How the pieces interlock:
- The FIPS nym transport dials peers through a local SOCKS5 proxy; the proxy routes each TCP stream through the mixnet (gateway → 3 mix hops → network requester), which performs the final TCP connection to the peer. The peer address must therefore be a TCP endpoint — find public peers at https://join.fips.network/.
- The
nym-socks5-clientis started by the entrypoint only when the generated FIPS config contains atransports.nymblock (FIPS_PEER_TRANSPORT=nym), and always before the FIPS daemon, so the proxy is listening by the time FIPS dials. - In nym mode, iptables drops the direct route to the peer: if the peer handshake completes, the traffic provably went through the mixnet.
Quick start
# 1. Generate a node identity (any machine with fipsctl, or reuse one):
# --stdout prints the nsec and npub instead of writing key files.
fipsctl keygen --stdout
# 2. Put the nsec into the environment:
export FIPS_NSEC=<your-nsec>
# 3. Build and run (native image; FIPS compiles for your host's arch):
docker compose up --build
Watch the logs: the entrypoint auto-discovers a Nym service provider,
bootstraps the SOCKS5 client (Nym SOCKS5 proxy ready …), and only then
starts FIPS. After the mixnet handshake completes (can take 30–120 s):
docker compose exec fips fipsctl show transports # nym transport: up
docker compose exec fips fipsctl show peers # test-us03: active
Switching transport: mixnet ↔ direct (TCP/UDP)
The single knob is FIPS_PEER_TRANSPORT in .env (or an inline override).
It selects how FIPS reaches the peer and whether the mixnet proxy runs
at all — the two are always in sync.
# Default — through the Nym mixnet (anonymized, ~1-2 s RTT):
FIPS_PEER_TRANSPORT=nym docker compose up -d # or just `docker compose up -d`
# Direct TCP (no mixnet, ~50-300 ms RTT). The nym client is NOT started:
FIPS_PEER_TRANSPORT=tcp docker compose up -d
# Direct UDP — also point FIPS_PEER_ADDR at the peer's UDP endpoint:
FIPS_PEER_TRANSPORT=udp FIPS_PEER_ADDR=54.183.70.180:2121 docker compose up -d
What changes under the hood for each value:
FIPS_PEER_TRANSPORT |
nym client | FIPS config block | peer endpoint used | direct route to peer |
|---|---|---|---|---|
nym (default) |
started, before FIPS | transports.nym |
FIPS_PEER_ADDR (TCP) via SOCKS5 |
firewalled off |
tcp |
not started | transports.tcp |
FIPS_PEER_ADDR (TCP) direct |
allowed |
udp |
not started | transports.udp |
FIPS_PEER_ADDR (UDP :2121) direct |
allowed |
To switch back to a direct link, set the value to tcp (no other change)
or udp (and swap FIPS_PEER_ADDR to the :2121 endpoint), then re-run
docker compose up -d. To return to the mixnet, set it back to nym.
Persist your choice by editing .env instead of prefixing the command.
The same node can be compared both ways — direct shows ~50-300 ms RTT,
the mixnet ~1-2 s, which is the visible signature that traffic is routing
through the Sphinx mix hops.
Verifying the traffic really crosses the mixnet
# The direct route to the peer is dropped — the only way packets reach
# the peer is via the nym-socks5-client:
docker compose exec fips iptables -L OUTPUT -v -n # DROP rule for peer IP
# Mixnet activity (Sphinx packet flow) in the nym client output:
docker compose logs fips | grep -i nym
# End-to-end data plane across the mesh. FIPS addresses every node by its
# key as <npub>.fips (each npub maps into fd00::/8); short names like
# `test-us03` are only local aliases for the peer you configured. Pick a
# node you are NOT directly linked to — grab a current npub from
# https://join.fips.network/ — so the ICMPv6 echo routes over the mixnet
# to your peer and then hop-by-hop across the mesh to the target:
docker compose exec fips ping6 -c3 <peer-npub>.fips
# A reply while the direct route is DROPped proves the traffic crossed the
# mixnet; the seconds-range RTT is the Sphinx path's signature, and a few
# extra hundred ms over reaching your own peer is the added mesh hops (a
# direct, non-mixnet connection would be ~30 ms).
The Nostr relay answers only over the FIPS mesh (fd00::/8) and on the container's loopback — inbound eth0 traffic, including the host's port-80 mapping, is dropped by the isolation rules. Check it from inside:
docker compose exec fips curl -s -H "Accept: application/nostr+json" http://127.0.0.1/
Configuration (.env)
| Variable | Default | Meaning |
|---|---|---|
FIPS_NSEC |
(required) | Node identity, fipsctl keygen --stdout |
FIPS_PEER_NPUB |
test-us03's npub | Peer to dial; empty = standalone |
FIPS_PEER_ADDR |
54.183.70.180:443 |
TCP endpoint in nym/tcp mode (use :2121 for udp) |
FIPS_PEER_TRANSPORT |
nym |
nym | tcp | udp — see "Switching transport" above |
NYM_SERVICE_PROVIDER |
(auto) | Network requester; empty = pick the best-scored from harbourmaster |
NYM_CLIENT_ID |
fips-nym-client |
Nym client identity (kept in the nym-data volume) |
With FIPS_PEER_TRANSPORT=tcp or udp the nym client is not started at
all and FIPS connects directly — useful as a baseline comparison.
Troubleshooting
could not auto-discover a Nym service provider— the harbourmaster API was unreachable or returned no providers; pick one manually from https://harbourmaster.nymtech.net/ and setNYM_SERVICE_PROVIDER.- Slow or failing mixnet bootstrap — service providers and gateways
vary in quality. Delete the client state and retry with another provider:
docker compose down -v && NYM_SERVICE_PROVIDER=<other> docker compose up. (The provider is baked into the client state at init; changing it requires wiping thenym-datavolume.) - Peer never becomes active — confirm the peer's TCP endpoint is reachable from the open internet (the network requester dials it from the Nym exit side, not from your machine).
- Never run this image under emulation — the image builds native for
a reason: under Rosetta/qemu, the FIPS daemon's ChaCha20-Poly1305
assembly (ring/BoringSSL) silently fails AEAD on larger frames; bloom
filter announces are dropped and multi-hop routing never converges,
while small control traffic keeps working — a maddeningly subtle
failure mode. Only the embedded amd64
nym-socks5-client(Nym ships no other arch) runs emulated on Apple Silicon, which it tolerates.
Notes
- The container's lifecycle follows the FIPS daemon; strfry, nginx and the
nym client run as background processes inside the same container and are
restarted with it (
restart: unless-stopped). - SSH (port 22, no auth) and tools like
tcpdump,nak,iperf3are inside the image for poking around — this is a demo image, do not expose it beyond your machine.