Solution: LP-0002 — Private M-of-N Multisig for LEZ

[duongja]

Summary

This PR submits a solution for LP-0002: Private M-of-N Multisig.

It adds:

• solutions/LP-0002.md

The solution links to the public implementation repository, narrated demo video, hosted testnet execution evidence, reviewer commands, and a checklist mapping the implementation to the prize success criteria.

Submission

• Prize: LP-0002 — Private M-of-N Multisig
• Solution file: solutions/LP-0002.md
• Implementation repo: https://github.com/duongja/private-multisig
• Implementation commit: ccf39786f7ffbbb5494fb1c2cebfd02699099bc3
• Implementation CI: green on ccf3978
• Demo video: https://drive.google.com/file/d/1vHEHCbz9aWfdcXFQjfUJpXHGlw9heY_u/view?usp=sharing

Key Evidence

• Example hosted testnet execute_private transaction:
  • e1805cae3ab6e46239cc823cc45d79e45a78ba80e57168e8fc50e240b9e70b59
• Hosted testnet final state includes:
  • proposal_status: Executed
  • proposal_approval_count: 2
  • target_account_data_utf8: threshold-approved

Reviewer Notes

The linked implementation repository includes:

• LEZ v0.2 program handlers for:
  • create_multisig
  • propose
  • execute_private
• private approval aggregation with proposal-scoped nullifiers
• reproducible standalone local sequencer flow with RISC0_DEV_MODE=0
• hosted LEZ testnet execution evidence
• Basecamp GUI that drives the real execution path
• reviewer-facing docs and cost evidence

Minimal reviewer command in the implementation repo:

./scripts/preflight.sh

Full local evidence:

export RISC0_DEV_MODE=0
./scripts/preflight.sh --with-localnet

Hosted testnet evidence:

export RISC0_DEV_MODE=0
./scripts/testnet-evidence.sh .local/testnet-evidence/latest

Notes

The lambda-prize fork and this PR branch are updated onto upstream master with the validator fix. The PR validation check is green on the latest submission commit.

The current implementation documents one known ecosystem limitation explicitly:

• official hosted-testnet per-transaction CU values depend on what the current LEZ explorer/RPC exposes

Proof-cycle and local transaction-cost evidence are included in the implementation repository.

[github-actions]

⚠️ Warnings

Warnings (non-blocking):

• ⚠️ No test files detected in linked repo.

ℹ️ Solution submission for LP-0002.
ℹ️ Checking repo: https://github.com/duongja/private-multisig

---

Automated check. See solution template and TERMS.

[duongja]

The current failing check is blocked before the validation script reads this solution file.

Failing run: https://github.com/logos-co/lambda-prize/actions/runs/30554437421

The failing step is Checkout PR head (untrusted data, never executed), with:

Refusing to check out fork pull request code from a 'pull_request_target' workflow

I opened a small workflow fix here:

• ci: allow fork checkout in submission validator #116

I also ran the repository validator locally against this PR branch after the LP-0002 fixes. The submission content passes the validator; the only remaining validator note is a non-blocking warning about test-file naming in the linked implementation repo.

[duongja]

Update: this is the same upstream validator issue already tracked in #109.

Canonical fix PR:

• ci: opt in to fork-PR checkout after the actions/checkout guard change #109

I had opened #116 with the same one-line workflow change, but closed it as a duplicate to avoid splitting the thread. Once #109 is merged into master, the validator can be rerun on this LP-0002 solution PR.

[weboko]

@duongja can you update your fork? ci should be working

[duongja]

Hello @weboko , done