标签：#zeroknowledge

Introduction Polymarket , and on-chain prediction markets like it, kept bothering me for one reason. Polymarket |世界最大の予測市場™ Polymarketは世界最大の予測市場であり、さまざまなトピックにわたって将来のイベントを取引することで、最新情報を入手し、知識から利益を得ることができます。 polymarket.com Who bet on what is visible in near real time. The moment a whale places a big bet on one outcome, everyone watching piles in behind them, and the odds move accordingly. That's not manipulation — it's just what happens with a public ledger. But it doesn't satisfy the simple wish to not reveal your prediction before everyone else does. So: could you build a prediction market that keeps your pick hidden until voting closes? To find out, I built Hidden League Forecast on Midnight , a privacy-focused blockchain. It's an MVP where you just guess the winner of a fictional soccer league (the World Cup just ended, so soccer was on my mind). Note What's a prediction market? A mechanism that expresses predictions about future events as prices. Think "which team will win the World Cup match," for example. If you want to learn more about prediction markets, this resource (Japanese) is a great start: https://zenn.dev/barabara/books/prediction-markets-structure The backend is written in Compact , Midnight's smart contract language. Note It combines the commit-reveal pattern with zero-knowledge proofs so that "the content of your prediction stays hidden, while only the aggregate stake becomes public." In this article, I'll walk through the contract code, showing what stays hidden and what becomes public at each step. Note This app runs on testnet. Demo Video After connecting Lace Wallet, you see your Shielded Address and balance. From here you can deploy a new market or enter an existing contract address to join one. The Overall Flow What's actually happening is simple. OPEN → REVEAL → AWAITING RESULT → RESOLVED → CLAIM Connect Lace Wallet, then deploy a market or join an existing one Pick one of 4 teams (Amber Foxes / Cedar Owls / Harbor Whales / Meadow Bears) and

I built a zero-knowledge secret sharing tool. Text and files are encrypted in the browser with AES-GCM 256 before upload - the server only ever sees ciphertext. The decryption key lives exclusively in the URL fragment (#k=...). URL fragments are never sent in HTTP requests (RFC 9110 §4.2.3), so Cloudflare Workers, D1, and R2 never see it - even in logs. A few things I tried to do right: Single-use by default: Durable Objects handle atomic read→decrement→delete with blockConcurrencyWhile, no race conditions on concurrent requests Paranoid mode: returns not_found instead of expired/burned, no timing oracle Revoke endpoint: delete a drop before it's read using a SHA-256'd token with constant-time comparison CLI: burnafter send / burnafter receive - full E2E from terminal, key never touches a browser - /security page with a live in-browser AES-GCM demo and a manual Node.js decryption snippet so you can verify without trusting me Stack: Cloudflare Workers + D1 + R2 + Durable Objects. No third-party crypto libs. Live: https://burnafterread.casablanque.com Source: https://github.com/casablanque-code/burnafterread Verify: https://burnafterread.casablanque.com/security