How to Prove Your Jewelry Was Made From Your Exact CAD File

You spent weeks on that model. You cleaned up every vertex, dialed in the tolerances, and exported a clean STL. Now you're about to email it to a casting house you've never visited, in a country you've never been to, and ask them to turn it into fifty rings.

Here's the question nobody in this industry likes to answer out loud: once your file is on their machine, what stops them from running it again — for someone else?

The trust gap in contract manufacturing

Contract casting runs on trust, and trust is exactly the wrong tool for the job. An NDA is a promise on paper; enforcing it means noticing the copy first, then hiring a lawyer in a foreign jurisdiction. "We only cast what we CAD" is a policy, not evidence. None of it gives you — the designer — anything you can actually hold up and verify later.

The uncomfortable truth: in most of the world's casting supply chain, you can't prove which file a physical piece came from. You're not verifying. You're hoping.

What proof actually looks like

A digital file has a fingerprint. Run your STL through a SHA-256 hash and you get a 64-character string that is unique to that exact file. Move a single vertex by a micron, re-export, and the hash changes completely. It can't be reversed, and it can't be faked.

That fingerprint is the anchor. The moment we receive your design, we compute its hash and write it — with the date and your authorship — as the first event in the piece's digital product passport. From there, every stage of production is chained to that same passport:

Stage	What gets recorded
Design received	SHA-256 hash of your STL/3DM, author, date
CAD adjusted	shrinkage-compensation %, hash of the adjusted file
Tooling made	molds, sizes
Cast	batch, gross weight
Finished	real measured weight, .925 assay
Verified	QC, size checked against a certified mandrel
Shipped / Delivered	carrier, tracking, confirmation

Every finished piece carries a passport that traces an unbroken line back to your fingerprint. Not a similar file. Not "a version of." That one.

Why a hash beats a watermark or a signed contract

Watermarks live inside the file and can be stripped. Contracts live in a drawer and depend on someone else's good behavior. A hash depends on nothing but mathematics: anyone — you, a customs officer, a buyer on the resale market years later — can re-compute the hash of the original file and check it against the passport. It either matches or it doesn't. No lawyer required.

And because the passport is published in GS1 EPCIS 2.0 — the same open standard the EU's Digital Product Passport (ESPR) is built on — it isn't a proprietary certificate that only we can read. It's structured, portable, and verifiable by anyone, forever. (New to passports? Start with what a digital product passport for jewelry actually is.)

What this does — and doesn't — prove

We're precise about this, because overpromising here would be its own kind of dishonesty:

• It proves that a physical piece descends from your specific file, and it documents every hand that touched it, with dates and measured facts (the weight in the passport is measured, not estimated).
• It does not replace copyright or registered-design protection. Provenance is evidence of origin; it is not a substitute for registering your IP with the appropriate authority. The two work together — the hash gives you the timestamped proof; the registration gives you the legal standing.

Think of it as a Carfax for your design: it won't stop every bad actor in the world, but it makes your piece the one with a paper trail — and it makes us the shop that chose to be provable instead of merely trusted.

See a real one

This isn't a roadmap slide. Our certificate system is in production today. You can open a live passport and inspect its events yourself: view a real product passport →

The bottom line

If you've ever wondered where your mold ends up, this is the answer. You send us a file; we send you finished pieces and a cryptographic record that ties each one to your design. You stop trusting. You start verifying.

Ready to see it on your own design? Request a quote → — send us your STL and we'll come back with pricing, lead time, and the provenance record that comes with every piece. Not sure what a full quote should include? Here's how to read a manufacturing quote.