Feature
Sealed to an international standard, not just a picture of a squiggle
When the last party signs, SignSwifly applies a PAdES digital seal with a cryptographic timestamp. Open the PDF in a standard reader and its signature panel shows whether the document has changed since it was sealed — alter one byte and the seal breaks.
In detail
What the seal contains
- PAdES (PDF Advanced Electronic Signatures) — the international standard for PDF sealing
- RFC 3161 timestamp from DigiCert, an independent timestamp authority, fixing the moment of completion
- Cryptographic digest of the exact document content at sealing
- The SignSwifly ID printed on every page before sealing, so the seal covers it
- Signature reason, location and contact embedded in the seal
What that means in practice
- Adobe Reader, or another PDF reader that checks signatures, shows whether the document has changed since it was sealed
- Today the seal uses SignSwifly’s own certificate: Adobe shows the document as unmodified, but the signer’s identity as unknown. A certificate on Adobe’s Approved Trust List, so Adobe shows the seal as trusted, is Coming soon
- Verify a document confirms that a copy is an unchanged SignSwifly original, by comparing its fingerprint with our records
- A change after completion breaks the seal, and the reader’s signature panel says so
- Anyone holding a single page can quote its SignSwifly ID, which leads back to the envelope's record
- The sealed file plus the certificate of completion, sealed the same way, form one portable evidence pack
Why it matters
The benefits
Checkable by anyone
Your counterparty’s PDF reader shows whether the document changed after sealing, and our verify page shows it came from SignSwifly.
Tamper evidence
Post-signing edits break the seal visibly.
Standards-based
PAdES is recognised internationally, not a proprietary format.
Seal your next document properly
Three envelopes a month are free, with no time limit. No credit card required.