Proving a Document Existed Without Storing the Document

ProofGate answers one narrow question well: can you prove a specific document existed at a specific moment in time? You submit a file or paste text, and ProofGate anchors it to the Solana blockchain so the timestamp is immutable, public, and independently checkable. It is running on Solana devnet, and you can try it at proofgate.io.

Nothing is stored, only the hash

The design decision that matters most is what ProofGate does not keep. When you upload or paste content, it is hashed to SHA-256 in the flow and only the hash is used. The document itself is never stored. That is the whole trick of a good attestation service: a hash is a fingerprint, so it is enough to prove that this exact content existed, but it reveals nothing about what the content actually is. You get the proof without handing over the secret, which means you can attest a contract, a dataset, or unreleased code without exposing any of it.

Anchored on-chain, verified by anyone

The flow is three steps. You submit content, up to 50 MB per file, with an optional label and an optional email for a receipt. ProofGate writes the hash to Solana through the Memo Program, which makes it immutable and public. Then you get a shareable link, and anyone can independently verify the proof against the chain without trusting ProofGate as a middleman.

Using the Memo Program rather than a bespoke smart contract is a deliberately small footprint. The Memo Program is a plain, well-understood way to attach data to a Solana transaction, so there is no custom program to audit and no contract state to maintain. The blockchain does the one job it is genuinely good at, an ordered and tamper-evident record, and everything else stays off-chain.

The use cases follow directly from that: intellectual property claims, timestamping the agreed version of a contract, proving research existed before publication, and tamper-proof audit trails. All of it comes down to a fingerprint and a public clock.