Vision
To provide the tools for creating verifiable proof in a world where artificial intelligence makes it ever harder to know what to trust.
Sellat. Trust needs proof.
About Sellat
Behind Sellat there is a simple question.
How can you prove that a file already existed on a given date and that its content has not changed since?
From a real claim to a product
Sellat was born from an insurance claim. The adjuster asked me to prove that a computer existed, in a specific state, before the incident. I had invoices, photographs and emails, but no independent proof of when each document had been created.
In the end a photograph taken before the incident was enough. But a question stayed with me: if a photo on its own does not prove when it was taken, how can we show that something already existed on a specific date?
Sellat was born from that question.
Today that need goes well beyond a photograph. A person may want to protect a creation, a company to record its operations, and an AI agent to leave verifiable evidence of what it did and when.
Sellat turns files, documents and records into digital proof of existence and integrity, verifiable by anyone, with no need to trust us.
One infrastructure for people, businesses and AI agents.
Trust needs proof.
Three principles we do not negotiate
Independent verification
Every proof can be checked with open tools and the public blockchain, without depending on sellat.app staying online. The verifier is open source.
The fingerprint, not the file
The proof engine works with the SHA-256 fingerprint. Creating a proof does not require handing over the original file.
Saying only what the proof demonstrates
A Sellat proof demonstrates existence and integrity at a point in time; not authorship or ownership. We would rather explain the limit than inflate the promise.
Who is behind it
Cristian Cascante
Founder
Full-stack engineer with more than fifteen years building web platforms, from custom WordPress to Docker infrastructure and AI-applied automation.
He designed and built Sellat end to end: the proof engine, the infrastructure and the product you are looking at.
The best way to understand it is to use it
Protect a file and keep its proof. No sign-up needed to start.
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