Drop in the original document and its Certificate of Integrity. This page checks that the document is the one that was certified, that the proof inside the certificate leads to a Bitcoin block, and that the block is real. It runs entirely in your browser: the document is never uploaded, and you do not need a Pasqio account or Pasqio’s word for any of it.
Optional, and not needed for the check above. It only says whether Pasqio anchored this hash and in which block — never whose document it is.
The document’s SHA-256 is computed here and compared with the hash the proof is about. The OpenTimestamps proof is then replayed operation by operation to the value it commits to, and that value must equal the merkle root inside the Bitcoin block’s 80-byte header.
The block header is fetched by your browser directly from blockstream.info and mempool.space, two independent public explorers, and its own hash is checked. Nothing in the result depends on a Pasqio server.
Save the .ots file attached to the certificate and check it at opentimestamps.org, or run ots verify from the reference client. The certificate’s third page explains both.