Solution: LP-0016 — Anonymous Forum with Threshold Moderation and Membership Revocation

[syafiqeil]

Submission: LP-0016 — Anonymous Forum with Threshold Moderation and Membership Revocation

Submitted by: Syafiq (Evice Labs)

Main Implementation (On-Chain + SDK): https://github.com/syafiqeil/logos-anonymous-forum
Implementation PR: logos-blockchain/logos-execution-zone#465
Basecamp Core Module: https://github.com/syafiqeil/anonymous_forum_core
Basecamp UI Module: https://github.com/syafiqeil/anonymous_forum_ui

Video Demo (SDK + On-Chain): https://youtu.be/Bj0GwITfYwM
Video Demo (Basecamp Integration): https://youtu.be/_9RvF-oS7jM

Summary

A complete implementation of the LP-0016 protocol built on the Logos Execution Zone (LEZ).
Members post anonymously via ZK proofs, moderators issue strikes through N-of-M threshold
consensus, and K accumulated strikes cryptographically reconstruct the member's Nullifier
Secret Key — enabling on-chain slashing and retroactive deanonymization of all prior posts.

The system spans three repositories: on-chain programs + Rust SDK
(logos-anonymous-forum),
a native Logos Basecamp core module (C++ Qt plugin via FFI), and a QML UI module — all
integrated end-to-end through Logos IPC.

Deliverables

• LEZ Program — membership_registry via SPEL framework with per-instance forum_id
  PDA, supporting multiple independent forum instances from a single deployment
• ZK Circuit — forum_membership_proof proving inclusion, non-revocation, and tracing
  tag integrity without revealing the poster's identity
• Moderation Library — logos_moderation_sdk: forum-agnostic, operates on abstract
  byte identifiers, compiled as both WASM (browser) and C-ABI shared library (Basecamp native)
• FFI Layer — liblogos_moderation_sdk.so + cbindgen-generated C header enabling
  cross-language interop from Rust to C++
• Basecamp Core Module — anonymous_forum_core: C++ Qt plugin built with
  logos-module-builder, wraps Rust FFI as Q_INVOKABLE methods published via Logos IPC
• Basecamp UI Module — anonymous_forum_ui: QML 3-view interface (Register, Post,
  Moderate) built with mkLogosQmlModule, communicates with core via logos.callModule()
• Two Forum Instances — K=2/N=2-of-3 and K=3/N=3-of-5, independently parameterised
• Protocol Spec — docs/protocol.md: formal unlinkability proofs, retroactive
  deanonymization analysis, N-of-M trust model, Basecamp integration architecture, and threat model
• IDL — Generated via SPEL CLI, machine-readable interface for all 4 instructions

Build & Run

# Standalone (logos-anonymous-forum repo)
git clone https://github.com/syafiqeil/logos-anonymous-forum
cd logos-anonymous-forum
./demo.sh                    # Build + SDK tests + program verification

# Full E2E test (requires LEZ workspace)
# See README.md for instructions on running within the LEZ environment

# Basecamp standalone app (clone both module repos side-by-side)
cd anonymous_forum_ui
nix run --impure

[github-actions]

⚠️ Warnings

Warnings (non-blocking):

• ⚠️ Prize references a Logos mini-app; no module.json found.

ℹ️ Solution submission for LP-0016.
ℹ️ Checking repo: https://github.com/syafiqeil/logos-anonymous-forum

---

Automated check. See solution template and TERMS.

[jzaki]

Implementation PR: logos-blockchain/logos-execution-zone#465
This PR adds to the LEZ repo. Lamda prize submissions are expected to use the LEZ, not necessarily modify it.

[syafiqeil]

Thanks for the feedback @jzaki! You're right. The initial submission incorrectly added code directly to the LEZ repo. I initially structured it within the LEZ workspace assuming that was the expected approach for SPEL-base programs.

I've since decoupled the project into a standalone repository (logos-anonymous-forum: https://github.com/syafiqeil/logos-anonymous-forum), which references LEZ as a git dependency rather than modifying it. The ## Repository section has been updated accordingly.

The standalone repo contains:

• On-chain program (programs/membership_registry/) — SPEL framework guest program
• Off-chain SDK (logos_moderation_sdk/) — forum-agnostic moderation library with FFI
• ZK circuit (program_methods/guest/) — membership proof
• demo.sh, membership_registry.idl.json, and CI workflow

The original LEZ PR (#465) is kept for reference but is no longer the primary implementation link.

[jzaki]

Can you explain if this is/isn't a logos module? How can a user use this within Logos Basecamp, and via what qt ui plugin/module?

[syafiqeil]

Yes, this is a Logos module, split into two Basecamp modules following the core/UI architecture:

• Core module (anonymous_forum_core (https://github.com/syafiqeil/anonymous_forum_core)): A C++ Qt plugin built with logos-module-builder. It wraps the Rust SDK (liblogos_moderation_sdk.so) via C-ABI FFI and exposes 12 Q_INVOKABLE methods (member, moderator, and aggregator operations) over Logos IPC (Qt RemoteObjects).
• UI module (anonymous_forum_ui (https://github.com/syafiqeil/anonymous_forum_ui)): A QML interface built with mkLogosQmlModule providing three views: Register, Post, and Moderate.

To run within Basecamp:

cd anonymous_forum_ui
nix run --impure

This launches a standalone Basecamp app with both modules loaded, demonstrating the full moderation lifecycle.

Video demo of the Basecamp integration: https://youtu.be/_9RvF-oS7jM

[syafiqeil]

The metadata.json module configs are in their respective repos:

• anonymous_forum_core/metadata.json (https://github.com/syafiqeil/anonymous_forum_core/blob/main/metadata.json) (type: core)
• anonymous_forum_ui/metadata.json (https://github.com/syafiqeil/anonymous_forum_ui/blob/main/metadata.json) (type: ui_qml).