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).

[jzaki]

@syafiqeil Does the video have audio? I can't here anything. Please msg me on the discord, might be easier to cover some points on a call

[syafiqeil]

I appreciate the offer @jzaki. But as a non native english speaker (indonesian), I'm much more effective communicating in writing than speaking. I hope that's okay.

Apologies about the audio, if narration text is not enough, I'll check and fix that.

If there are specific points that need clarification or anything misaligned with lp-0016 requirements, I'm happy to address them in detail here. Please let me know what needs attention and I'll respond thoroughly.