How do I verify a blockchain timestamp?

Open the transaction in your certificate on a public explorer like Etherscan, read the recorded SHA-256 hash, then re-hash your file and confirm the two match. If they match, the file is unchanged and the blockchain proves when it existed.

Can anyone verify the timestamp, or just me?

Anyone can. The record is on a public blockchain, so any third party can independently confirm it without an account and without trusting BlockchainSign.

Do I need our service to verify a timestamp?

No. Your certificate contains everything needed to verify the record directly on Etherscan, so the timestamp stays verifiable forever — even if our service is no longer available.

Blockchain Timestamp Verification

Blockchain timestamp verification is the process of confirming that a file existed at a specific time and hasn't changed since — by checking its fingerprint against the record on a public blockchain. Because the record is on a decentralized ledger, anyone can verify it independently, with no account and no trust in the service that created it.

How to verify a blockchain timestamp

Open the blockchain record — use the transaction link in your certificate to view it on a public explorer like Etherscan.
Read the stored hash — find the SHA-256 fingerprint that was recorded on-chain.
Re-hash your file — generate the SHA-256 hash of your file and confirm it matches the one on the blockchain.

If the hashes match, the file is provably the same one that was timestamped, and the blockchain proves exactly when. The full walkthrough with screenshots is on the how it works page.

Independently verifiable

Anyone can confirm the record on a public block explorer — no account and no trust in us required.

Tamper-proof

Any change to the file changes its hash, so verification instantly reveals if a document was altered.

Permanent

The record lives on Ethereum forever, so your timestamp stays verifiable even if our service disappears.

What verification proves

A successful check answers two questions at once: did this exact file exist by this date? and has it been changed since? That makes blockchain timestamp verification useful for confirming authorship, the integrity of a contract or document, or that a file is unmodified — all without exposing the file itself, since only its hash is ever published.