Prove your work existed at an exact moment in time.
CardanoWall anchors any file to a tamper-proof timestamp on the Cardano blockchain. You get a receipt that proves it existed at that moment, verifiable by anyone, forever, with no account and no middleman to trust.
Need privacy? Seal a file so only the people you choose can open it, post-quantum by default.
Timestamps you can prove.
Anyone can put yesterday's date on a file they made today, so a date you set yourself proves nothing. A CardanoWall receipt is different: it can only exist if you really did create the file before the moment it was sealed on the Cardano blockchain. And anyone, forever, can verify that for themselves.
How a record is made.
Your device does the cryptography. The Cardano network keeps the dated receipt. Anyone can verify it forever, and if you sealed it for someone, only they can open the contents.
- 01
Your device prepares it
We compute a cryptographic fingerprint of your file in the browser. That fingerprint is the proof. If you also want to preserve the file itself or share it with a recipient, we encrypt it on your device first — your plain file never leaves your machine.
- 02
Cardano keeps the receipt
A tiny anchor goes on the Cardano mainnet. It is small, public, and dated, but it gives away nothing about your file.
- 03
Anyone can verify it
Anyone with the transaction reference can confirm the date straight from the public chain, forever, with no account and no trust in us. If you sealed the record, only your recipient can open the contents; everyone else sees noise.
An open standard, with a gateway you can run yourself.
Label 309 is the proof-of-existence standard we wrote for the Cardano community, now going through the official CIP process. CardanoWall is the first gateway to it: an API that turns a publish-ready record into a Cardano transaction, with a ready-made interface on top. We are open-sourcing that gateway, so you will be able to self-host it and publish straight from your own wallet with no service fee, or build a competing service on the same standard. Our hosted app stays our product; the standard and the gateway underneath belong to everyone.
Read the standardEvery part is in the open.
Our SDKs (TypeScript, Python, and Rust), the command-line tool, and the cryptography library are open source on GitHub: Apache-2.0 for the code, CC-BY-4.0 for the standard. Anyone can run their own verifier, audit our crypto, or build a competing service against the same standard. The cardanowall.com web app is one implementation — if we ever raise prices or disappear, your records keep working without us.
Quantum-safe confidentiality, on by default.
Seal a record and its contents are encrypted by default with a post-quantum hybrid (X-Wing), so they stay private even against a future quantum computer that records traffic today. Encryption is always optional, and the rest of the stack uses the same proven cryptography as Signal and WireGuard.
- Files only leave your device encrypted
- By default the file stays with you — only its fingerprint is published. If you also keep an encrypted copy on Arweave (so a future local edit can't break the proof), the file is encrypted in your browser first. We only ever handle ciphertext — even we can't read it.
- No vendor lock-in
- Open standard, open SDKs. Any verifier built against Label 309 can confirm a receipt without us.
- Cheap and final
- A few cents per record. No subscription. The proof outlives the company.
Where CardanoWall began.
CardanoWall launched in 2021 as the first proof-of-existence service built on Cardano. People used it to put a permanent, dated fingerprint of their work on-chain years before anyone wrote a standard for it. The video is the original introduction — the very first implementation, and the idea behind it.
Today the project is reborn on Label 309: an open standard we designed carefully from the ground up. It does far more than the original — and it hands every tool to developers and users to create proofs of existence with no lock-in to any vendor, or even to this site.
The original 2021 introduction.
Make your first sealed record.
It takes about a minute. The proof lasts as long as the Cardano network does.