How sealing works, and what it proves
What happens to a document at the moment the last person signs.
When the last signature lands, SignSpry does four things:
- Flattens every field value into the page — signatures, text, dates, stamps
become part of the document rather than a layer over it.
- Appends a certificate of completion listing every party, every event, the
times, and the IP address each action came from.
- Hashes the result with SHA-256.
- Seals it — a PKCS#7 signature over those exact bytes, embedded in the PDF.
What that proves
The seal covers the whole file. Change one character, one pixel, one byte of metadata, and the hash changes and the seal no longer matches. There is no way to alter a sealed document without it being detectable.
It does not prove the document is true, or that the terms are fair, or that the person who typed a name was who they claimed. It proves the document has not changed since it was sealed, and it ties that to the audit trail of how it got there.
Checking a document
Verify a document takes any PDF and tells you whether the seal is intact and what the audit trail says. No account needed — send the link to a bank, a counterparty, or a court clerk.
More than one signature
An envelope signed with Aadhaar eSign carries a signature per signer as well as our seal, and your PDF reader will say the earlier ones cover an earlier revision of the file. That is correct behaviour — see Why a signed PDF shows several signatures.
Timestamps
The seal also carries an independent timestamp proving when it was applied, from an authority that isn't us.