Demo mode — for demonstration purposes only. Storage is temporary on Solana Devnet and NOT permanent on Solana Mainnet.
Chronostamp.io

Prove your file existed today,
forever on Solana.

Select a file, generate a SHA-256 hash in your browser, and anchor it immutably on-chain. No file ever leaves your device.

1

Select your file

Drop your file here, or browse

Any file type · Any size

2

Identify yourself

Each use consumes one token from your account. You may use the FREE key if enough tokens are available.

3

Generate the proof

Select a file to continue.

How it works
  1. Select a file — it never leaves your device. Only the hash of the file is stored on Solana.
  2. Optionally provide your name, company and email. Those information will be displayed for the matching proofs when checking proof. It may be used to help other people to contact you. If you don't provide those information, you are STRONGLY encouraged to provide a secret to prove you actually did the registration.
  3. It is recommended to provide a secret. The hash of this secret is stored on Solana and will be compared to the hash of the secret when checking proof.
  4. Your browser computes SHA-256 hashes and anchors them on Solana.
  5. Keep the transaction signature as immutable proof.