SolNotary

03 //Overview

A web app that proves what someone knew, and when. A signed-in Solana wallet submits a short text; the server adds a live BTC, ETH and SOL price snapshot and a secret salt, hashes them together and writes only the hash to Solana in seconds. Paying an exact amount later publishes the text, with a public page anyone can check.

04 //The problem

Predictions, sealed bids and ideas are only worth something if you can prove later that they came first, without giving them away early. Screenshots and emails can be faked, and posting the text publicly reveals it. The client wanted a commitment that a public blockchain can vouch for, fast and cheap, with publishing as the paid step.

05 //The solution

• Sign-in by wallet signature: a one-time challenge checked with ed25519 on the server, with no passwords or email
• Text, market snapshot and secret salt hashed with SHA-256; only the hash goes on Solana, as a memo transaction confirmed in seconds
• Unlock by an exact payment in SOL, USDC or USDT with a reference memo, matched by webhook or by checking a transaction on-chain
• Public pages that reveal the text and salt, recompute the hash in the visitor's own browser and compare it with the chain
• Share cards rendered on the server, and row-level security that keeps sealed records unreadable with the public key
• A read-only admin overview of every record and payment that never shows sealed text

06 //Built with