Cryptographic proof of public statements on Hedera.

signalarchive.org · HashScan topic

Proof detail view showing deletion metadata, severity scoring, and Hedera HCS attestation.

• Monitors 40 tracked public accounts on X/Twitter continuously
• Archives every tweet to PostgreSQL with a deterministic SHA-256 hash
• Submits each hash to a public Hedera HCS topic — timestamped, permanent, independent of this service
• Detects deletions via oEmbed polling and submits a second on-chain attestation
• Scores each deletion for public interest significance using Claude Opus
• Serves proof via a public web interface; every attestation links directly to HashScan

Public figures delete statements after they become inconvenient. Screenshots can be fabricated. This system provides a different class of evidence: a cryptographic commitment to the tweet's exact content, submitted to Hedera's public distributed ledger within seconds of posting — before any deletion occurs. The proof exists independently of this service — anyone can verify it directly against Hedera's public network.

capture → hash → attest → detect deletion → score → display proof

1. Capture — tier-based ingestion daemon polls accounts. Priority accounts checked hourly, standard accounts every 4 hours.
2. Hash — SHA-256 over canonical JSON (content, author ID, timestamp, media URLs). Deterministic and reproducible by anyone with the original data.
3. Attest — hash submitted to HCS topic 0.0.10301350 on Hedera mainnet. Consensus in seconds.
4. Detect — deletion worker checks archived tweets against X's oEmbed API. 404 → flagged, second HCS attestation submitted.
5. Score — Claude Opus rates each deletion 1–10 for public interest significance. Heuristic fallback if API is unavailable.
6. Verify — every proof page links to HashScan. No trust required.

signal-archive/
  apps/
    web/        Next.js frontend + API routes
    worker/     BullMQ job consumers (deletion detection, HCS, ingestion)
  packages/
    db/         Drizzle schema + migrations
    shared/     Types, canonical hash, constants
  scripts/      Operational scripts (seeding, backfill, diagnostics)
  deploy/       Docker Compose, Dockerfiles, VPS setup

• HCS 0.0.10301350 — tweet attestations and deletion records (mainnet)
• HCS 0.0.10310903 — donation receipts via HIP-551 atomic batch
• HCS-2 registry 0.0.10388911 — machine-readable topic registry at signalarchive.org/registry
• HIP-551 — atomic batch bundles HCS submission + optional NFT mint into a single atomic transaction
• HIP-657 dNFT 0.0.10314265 — supporter badge NFTs with dynamic metadata
• 3,000+ messages live on mainnet as of March 2026

Phase 1: 40 accounts across the US federal executive, White House / Cabinet, key legislative figures, and affiliated crypto/financial projects. Coverage is explicit and manually curated — only accounts added to the tracked list are monitored.

Full list: docs/SEED_ACCOUNTS.md

npm install
npm run dev          # web + worker (turbo)
npm run typecheck    # run after every change
npm run test
npm run db:generate  # after schema changes
npm run db:migrate

Local services setup, environment variables, and deployment details: docs/DEVELOPMENT.md

• Coverage is limited to explicitly tracked accounts — tweets from unmonitored accounts are not archived
• Ingestion relies on X's public API; availability depends on X's access policies
• Tweet media (images, video) is not currently archived — only text content and metadata are preserved
• The system records what existed before deletion; it cannot retroactively capture tweets deleted before monitoring began
• Deletion detection uses oEmbed polling, which has inherent latency — very brief deletions may not be caught

Submitted to the Hedera Hello Future: Apex Hackathon 2026, Open Track.

License: All rights reserved.