nim-chat-poc/simulations/mix_lez_chat

Mix + LEZ RLN Chat Simulation

End-to-end private chat between two logos-chat-module clients over a 4-node mix network with LEZ-backed RLN spam protection.

Two logoscore instances (sender + receiver) establish an X3DH key agreement via an out-of-band intro bundle, then exchange double-ratchet-encrypted messages routed through 3-hop Sphinx onion routes with per-hop RLN proof generation and verification. Node 0 mounts the rln_gifter service; nodes 1-3 and both chat clients register RLN memberships on-chain via the gifter protocol. The sender publishes via lightpushPublish(mixify=true), the mix exit node verifies the RLN proof before fanning out via gossipsub relay, and the receiver consumes the message via a Waku filter subscription.

macOS

Prereqs: nix (with flakes), Docker, cargo-risczero, SSH access to GitHub.

git clone -b feat/logos-delivery git@github.com:adklempner/logos-chat.git
cd logos-chat && bash simulations/mix_lez_chat/setup_and_run.sh

First run: ~15-25 min. Re-runs: bash simulations/mix_lez_chat/run_simulation.sh --fresh (~5 min).

Linux (native)

Prereqs: nix (with flakes), Docker, cargo-risczero, SSH access to GitHub.

git clone -b feat/logos-delivery git@github.com:adklempner/logos-chat.git
cd logos-chat && bash simulations/mix_lez_chat/setup_and_run.sh

Same as macOS. On x86_64 Linux this should work out of the box. On aarch64 Linux, guest zkVM binaries must be pre-built on another platform (rzup doesn't support aarch64-linux) and the wallet module nix build needs RISC0_SKIP_BUILD_KERNELS=1.

Linux (via Docker)

Prereqs: Docker with 24GB RAM allocated.

git clone -b feat/logos-delivery git@github.com:adklempner/logos-chat.git
cd logos-chat && bash scripts/run_in_docker.sh

The pre-built image (ghcr.io/adklempner/logos-chat-sim) is pulled automatically (~8.5GB download). Guest zkVM binaries must exist on the host from a previous macOS/x86_64 build, or set GUEST_BINARIES_DIR.

Each sim run: ~10 min (clone + sequencer build + sim). To force a local image rebuild: REBUILD_IMAGE=1 bash scripts/run_in_docker.sh.

Pass criteria

ALL 15 CHECKS PASSED — 4 mix nodes mounted, gifter service, LEZ RLN active, sender+receiver initialized/started/mix-mounted, intro bundle created, messages sent and received.

Architecture

logoscore (per mix node)                    logoscore (per chat client)
├── wallet_module (LEZ wallet)              ├── wallet_module (LEZ wallet)
├── liblogos_rln_module (RLN proofs)        ├── liblogos_rln_module (RLN proofs)
└── delivery_module (Waku mix relay)        └── chat_module (logos-chat-module)
    ├── liblogosdelivery.so                     ├── chat_module_plugin.so
    └── mix + relay + filter + gifter           └── liblogoschat.so
                                                    └── mix client + filter + gifter client

Node 0 runs the RLN gifter service. Nodes 1-3 register via gifter on startup. Chat clients also register via gifter when startChat() runs.

Configuration

Override defaults via environment:

Variable	Default	Description
SIM_NUM_NODES	4	Number of mix relay nodes
SIM_BASE_TCP_PORT	60001	First node's TCP port (increments per node)
SIM_BASE_DISC_PORT	9001	First node's discv5 UDP port (increments per node)
SIM_CLUSTER_ID	99	Waku cluster ID
SIM_LOG_LEVEL	INFO	Node log level (TRACE, DEBUG, INFO, WARN, ERROR)
SIM_CHAT_RECV_PORT	60010	Chat receiver TCP port
SIM_CHAT_SEND_PORT	60011	Chat sender TCP port
SIM_KADEMLIA_MIN_WAIT	30	Minimum seconds to wait for kademlia propagation
SIM_RECEIVER_MIN_WAIT	15	Minimum seconds to wait for receiver to join mix
SIM_DELIVERY_TIMEOUT	120	Max seconds to wait for message delivery

Example — fast iteration with verbose logging:

SIM_LOG_LEVEL=TRACE SIM_KADEMLIA_MIN_WAIT=10 SIM_RECEIVER_MIN_WAIT=5 \
  bash simulations/mix_lez_chat/run_simulation.sh --fresh

--fresh behavior

When --fresh is passed:

• Kills all existing logos_host processes
• Cleans /tmp/logos_* Qt RemoteObjects sockets
• Removes .sim_state/ directory
• Removes sequencer state (rocksdb/, bedrock_signing_key)
• Rebuilds and restarts the sequencer
• Redeploys RLN programs via run_setup

Without --fresh, reuses existing sequencer if port 3040 is already bound.

Troubleshooting

Re-run with fresh state:

bash simulations/mix_lez_chat/run_simulation.sh --fresh

"Sequencer failed to start" — port 3040 already in use:

kill $(lsof -ti tcp:3040) && bash simulations/mix_lez_chat/run_simulation.sh --fresh

"run_setup failed" / "Timeout waiting for account" — stale guest binaries or wallet state:

rm -rf vendor/logos-lez-rln/lez-rln/methods/guest/target
rm -f vendor/logos-lez-rln/dev/wallet_config.json vendor/logos-lez-rln/dev/storage.json
bash simulations/mix_lez_chat/setup_and_run.sh

"Sender started FAIL" — stale Qt RemoteObjects sockets:

rm -f /tmp/logos_*
bash simulations/mix_lez_chat/run_simulation.sh --fresh

Docker logs are rescued to ./docker-sim-logs/ on failure.

Adapting for other LEZ programs

This simulation provides a complete mix network infrastructure that other logos modules can reuse for testing. To test your own module:

What the sim provides

• 4 logoscore mix nodes with delivery_module (Waku relay + mix + RLN)
• LEZ sequencer with deployed RLN programs
• RLN gifter service on node 0
• Wallet modules for on-chain transactions

What you replace

The chat_module sender/receiver instances (phase 5 of run_simulation.sh). Your module needs:

1. A C++ Qt plugin implementing PluginInterface (see chat_module_plugin.cpp)
   • initLogos(LogosAPI*) — receive the LogosAPI instance
   • eventResponse(QString, QVariantList) signal — mandatory per logos-liblogos contract
   • Methods exposed via LOGOS_METHOD for logoscore -c invocation
2. A shared library with your program logic (like liblogoschat.so)
3. RLN integration — wire setRlnConfig to pass RLN credentials from the C++ plugin to your library
4. EVENT: stderr fallback — on Linux, Qt signal forwarding from plugin to logoscore doesn't work across the FFI thread boundary. Write event data to stderr in EVENT:name:data format (gated by LOGOS_EVENT_STDERR env var) for cross-platform reliability.

How to stage your module

MDIR=$(mktemp -d)
mkdir -p "$MDIR/your_module"
cp your_module_plugin.so "$MDIR/your_module/"
cp libyour_library.so "$MDIR/your_module/"
echo '{"name":"your_module","version":"1.0.0","type":"core",...}' > "$MDIR/your_module/manifest.json"

logoscore -m "$MDIR" \
  -l "liblogos_execution_zone_wallet_module,liblogos_rln_module,your_module" \
  -c "liblogos_execution_zone_wallet_module.open($WALLET_CONFIG,$WALLET_STORAGE)" \
  -c "your_module.init(@config.json)" \
  -c "your_module.start()"

Reference

• chat_module_plugin.cpp — complete working example with RLN, gifter, mix, and event emission
• delivery_module_plugin.cpp — more complex example with full RLN fetcher integration
• run_simulation.sh — orchestration, module staging, and verification patterns

Logs

All logs in simulations/mix_lez_chat/.sim_state/:

• node0.log – node3.log — mix relay nodes
• chat_receiver.log — receiver chat module
• chat_sender.log — sender chat module
• sequencer.log — LEZ sequencer