How to timestamp design files and drawings
Design work gets shared early and widely: with manufacturers, contractors, investors, competitors on a shortlist. A dated, tamper-proof record of what you had before you sent it out is cheap insurance, and it is the use case our own customers reach for most.
Why design files specifically
Engineering and design documents sit in an awkward gap. They are commercially valuable and frequently disputed, but the usual protections fit badly:
- Patents protect inventions, take years, cost thousands, and most drawings never justify one.
- Copyright covers the drawing as a work, automatically, but not the design it depicts — and it does not date anything.
- NDAs are contractual promises. Useful, but they do not establish what you disclosed or when.
What is usually contested is narrower and more factual: did this design exist, in this form, on this date? That is exactly what a timestamp answers.
What to timestamp
- CAD and native files — STEP, DWG, SLDPRT, F3D. The native file is what a copier will not have.
- Schematics and PCB layouts, including the netlist and BOM.
- Renders and general arrangement drawings shared with third parties.
- Revision packs — timestamp each release, not just the first.
- The disclosure itself — a hash of the exact file set you sent, on the day you sent it.
That last one is quietly the most valuable. If you can show precisely which files went to whom and when, an NDA becomes enforceable in a way it usually is not.
How it works
- Hash the file. SHA-256, computed in your browser. The design never leaves your machine — non-negotiable for confidential work.
- Record the hash on Ethereum. Public, permanent, and revealing nothing about the design.
- File the certificate with the project records.
To prove the point later, re-hash the archived file and compare it against the on-chain record.
Confidentiality
Nothing about the geometry, the part names or the file size is disclosed. A hash is a one-way fingerprint — 64 hexadecimal characters that cannot be reversed into the file. This is what makes the approach viable for pre-patent and pre-launch work, where publication would destroy the very thing you are protecting.
Note the contrast with defensive publication, which establishes prior art precisely by disclosing. Timestamping gives you a dated record while keeping the design secret. If you later want prior art, you can publish then.
Before you disclose
The sequence that costs nothing and helps most:
- Timestamp the design package before sending it anywhere.
- Send under NDA, and keep the transmittal record.
- Timestamp each subsequent revision.
- Keep archived copies byte-identical — a re-save changes the hash.
- For inventions you intend to patent, talk to an attorney early; a timestamp supports a priority narrative but is not a filing.
What the record establishes is existence and integrity at a time, not inventorship — see proof of existence vs proof of authorship. A dated series of revisions showing a design evolving is, however, something only the originating team can produce.