Contracts, proposals, whitepapers, invoices and reports usually end up as PDFs, and PDFs are often what people argue over: which version was sent, and when. A PDF carries more date information than most formats, including, sometimes, a third-party time. Here is what a PDF records, which of those dates mean anything, and how to freeze the exact file you send.
Short answer: A PDF’s created and modified dates are written by the software that made it and can be changed. To show a contract, proposal or whitepaper existed before a date, timestamp the exact PDF with TimeBinder before you send it, and keep that copy unchanged. A TimeBind shows that the exact file existed no later than the recorded time and still matches its fingerprint. It doesn’t show who made it or what a court will make of it.
Disclosure: I’m Inna Hall, co-founder of TimeBinder, the file timestamping tool this guide uses. This page is general information, not legal advice.
Table of Contents
Where a PDF keeps its dates
- The document information dictionary: CreationDate and ModDate, plus fields such as Producer (the software that wrote the PDF) and Creator (the app it came from). PDF 2.0 deprecates most of this dictionary but keeps the two dates.
- XMP metadata: an embedded XML packet with create, modify and metadata dates, and often a document ID and instance ID that change between versions.
- Incremental updates. Many tools save changes by appending them to the end of the file, so an edited PDF can still contain its earlier revision. Each update can carry its own dates.
- Annotations and form fields can each carry a modification date.
Signatures and time-stamps
A digitally signed PDF includes a signature dictionary. The signing time in it (the /M entry) is supplied by the signer’s software, so on its own it is only as reliable as that computer’s clock. A signature can also include an embedded time-stamp token from a Time Stamping Authority under RFC 3161, which is a third-party statement that the signature existed at that time. Long-term signature profiles (PAdES) add document time-stamps so a signature can be validated years later. If you use an e-signature platform, its certificate of completion records the signing events on the platform’s side.
For the differences between a Time Stamping Authority and an anchored timestamp, see RFC 3161 vs a blockchain timestamp.
Which dates are weak, and which are not
- Weak: CreationDate, ModDate and XMP dates, which come from whoever made the file and can be edited. Printing to PDF or exporting again creates new dates.
- Stronger: an embedded RFC 3161 time-stamp, an e-signature platform’s audit trail, and emails held by the other side, because someone other than you recorded the time.
- Gaps: most PDFs you send (proposals, drafts, whitepapers, pitch decks) are never signed or time-stamped at all, and platform records belong to an account you may lose access to.
What to freeze
- The exact PDF you send, not a re-export. Exporting again from Word or InDesign produces a different file with new dates and a different fingerprint.
- The source file (DOCX, InDesign package, Google Docs export) at the same moment, to show the PDF came from your working file.
- Earlier drafts and redlines, particularly for contracts, so you can show what changed between versions.
- The signed copy and the platform’s certificate of completion, once signing is done.
A simple routine
- Export the PDF you are about to send, and stop editing it.
- TimeBind the PDF and its source file together in TimeBinder.
- Send that same PDF. If anyone asks for changes, export and TimeBind the new version before sending it.
- After signing, TimeBind the fully signed PDF and keep the certificate of completion with it.
Which plan fits
The free plan gives you 1 Token a month, which is one Pooled TimeBind of up to 10 files. No credit card is required for the free plan. A Pooled TimeBind is usually recorded within 24 to 48 hours, and often sooner, depending on Bitcoin network activity; an ASAP TimeBind costs 3 Tokens and gets its own Bitcoin transaction straight away.
For more milestones, Essential is US$20 a month for 5 Tokens (5 Pooled, or 1 ASAP plus 2 Pooled). Expert is US$50 a month for 15 Tokens (15 Pooled or 5 ASAP), and unused Tokens roll over. Verification is free. See pricing.
What a timestamp does and doesn’t do
TimeBinder anchors each file’s SHA-256 fingerprint to Bitcoin and gives you a Proof of Time Certificate. That is verifiable evidence of when a file existed: it shows the file existed no later than the anchor date, and any later change to the file is detectable. An ASAP TimeBind can be checked directly on the Bitcoin blockchain without relying on TimeBinder; a Pooled TimeBind is verified through TimeBinder. Your file is hashed in your browser and never uploaded.
It doesn’t show who made the work or who owns it, it doesn’t stop copying, and it doesn’t cover a version you didn’t timestamp. A timestamp does not show what the parties agreed or whether a contract is valid. See the signed deed version example scenario and legal document verification.
Frequently Asked Questions
Can you trust the creation date in a PDF?
Not on its own. The CreationDate and ModDate in a PDF, and the matching XMP dates, are written by the software that made or saved the file, using that computer’s clock. They can be edited with ordinary PDF tools.
Does a digital signature prove when a PDF was signed?
It depends. The signing time shown in many signatures comes from the signer’s computer. A signature that includes an embedded time-stamp token from a Time Stamping Authority (RFC 3161) is much stronger, because a third party vouches for the time.
Is an e-signature certificate of completion enough?
It is a good third-party record of when the signing events happened on that platform. It lives in the platform’s account, though, and it covers the signed document, not your earlier drafts.
Why did my PDF’s fingerprint change after I filled in a form field?
Saving a PDF after any change, even a form field or an annotation, changes its bytes. Many tools save PDFs as incremental updates appended to the end, so the earlier version may still be inside, but the file as a whole is new.
Plan details were checked against timebinder.io/pricing on 29 October 2026.
