Blockchain timestamp verification
Blockchain timestamp verification is the process of confirming that a file existed at a specific time and has not 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.
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.
How to verify a blockchain timestamp
- Open the blockchain record — use the transaction link in your certificate to view it on a public explorer such as 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 is on the how it works page.
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.