PDF glossary
Byte range
The parts of a PDF file a digital signature covers — the whole file except the space reserved for the signature itself.
A signature can’t sign its own bytes, so a PDF signature lists the ranges it covers: everything before and after its own value. Anything appended later — another signature, an edit — falls outside it.
A verifier therefore checks two things: that the covered bytes are unchanged, and whether the signature covers the whole file or something was added after it.
In PDF-SDK
Verification reports, for each signature, whether it covers the whole file or the document was changed after it.
Verify PDF signaturesLast reviewed