https://github.com/systemslibrarian/crypto-lab-time-lock-puzzle
https://github.com/systemslibrarian/crypto-lab-time-lock-puzzle
Last synced: 10 days ago
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- Host: GitHub
- URL: https://github.com/systemslibrarian/crypto-lab-time-lock-puzzle
- Owner: systemslibrarian
- Created: 2026-06-28T17:00:58.000Z (23 days ago)
- Default Branch: main
- Last Pushed: 2026-06-28T23:36:21.000Z (22 days ago)
- Last Synced: 2026-06-29T01:15:42.144Z (22 days ago)
- Language: TypeScript
- Size: 62.5 KB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Time-Lock Puzzles
An interactive, browser-only demonstration of the **Rivest–Shamir–Wagner (RSW) time-lock puzzle** — part of the [Crypto Lab](https://systemslibrarian.github.io/crypto-lab/) suite.
## 1. What It Is
A **time-lock puzzle** seals a message so that recovering it requires a fixed amount of *sequential* computation — work that cannot be meaningfully parallelised. This demo uses the RSW construction: pick an RSA-style modulus `N = p·q` and a base `a`; the answer is `b = a^(2^t) mod N`, reachable only by squaring `t` times in order (`xᵢ₊₁ = xᵢ² mod N`). The message itself is sealed with real **AES-256-GCM** under `SHA-256(b)`. Unlike ordinary encryption, there is no shared secret key — *anyone* can open it eventually; security comes from elapsed sequential time, tuned by the step count `t`. The factorisation of `N` is a trapdoor that lets the creator (and only the creator) open it instantly.
## 2. When to Use It
- **Sending data into the future / delayed disclosure** — escrow or dead-man switches where openability must not depend on trusting a custodian.
- **Sealed-bid auctions** — bids that cannot be opened before a deadline, with no trusted auctioneer holding the plaintext.
- **Randomness beacons & commit-reveal** — force a delay between fixing an input and learning the output so no one can grind the result.
- **As the engine of a Verifiable Delay Function (VDF)** — the same squaring chain underlies Pietrzak/Wesolowski VDFs, which add a fast-to-check proof.
- **When NOT to use it:** anything needing instant, key-based access control, or a *guaranteed wall-clock* delay — solve time scales with the *speed of one machine*, so faster hardware opens it sooner. Time-lock puzzles bound parallel speed-up, not absolute time.
## 3. Live Demo
**[systemslibrarian.github.io/crypto-lab-time-lock-puzzle](https://systemslibrarian.github.io/crypto-lab-time-lock-puzzle/)**
Type a secret, choose a difficulty (number of sequential squarings `t`) and modulus size, and generate a puzzle. Then solve it: watch the squarings accumulate in a Web Worker with live progress and a per-device time estimate. Contrast three openings — the **honest sequential solve**, a **cheat** that skips the work (rejected by AES-GCM, failing closed), and the **creator's trapdoor** that opens instantly via `φ(N)`. All cryptography runs in your browser with JavaScript `BigInt` + WebCrypto; nothing is sent to a server.
## 4. How to Run Locally
```bash
git clone https://github.com/systemslibrarian/crypto-lab-time-lock-puzzle
cd crypto-lab-time-lock-puzzle
npm install
npm run dev
```
Run the test suite with `npm test` (25 tests covering the math, including the load-bearing invariant that the sequential solve equals the trapdoor open). No environment variables are required.
## 5. Part of the Crypto-Lab Suite
> One of 60+ live browser demos at
> [systemslibrarian.github.io/crypto-lab](https://systemslibrarian.github.io/crypto-lab/)
> — spanning Atbash (600 BCE) through NIST FIPS 203/204/205 (2024).
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*"Whether you eat or drink, or whatever you do, do all to the glory of God." — 1 Corinthians 10:31*