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Getting started

1 min read · Guides

Getting started

This guide walks through the fastest path to understanding CNML: install the packages, generate a sample certificate, and verify it.

Install the packages

CNML ships as npm packages under the @oiml scope. Install the ones you need:

npm install @oiml/cnml-crypto    # the verification pipeline
npm install @oiml/cnml-schemas   # per-Recommendation JSON Schemas
npm install @oiml/cnml-xml       # CNML XML parser and serializer

npm install @oiml/cnml-crypto    # the verification pipeline
npm install @oiml/cnml-schemas   # per-Recommendation JSON Schemas
npm install @oiml/cnml-xml       # CNML XML parser and serializer

Or clone the repository for the full experience (web app, CA server, test vectors):

git clone https://github.com/oimlsmart/cnml.git
cd cnml
pnpm install
pnpm dev

git clone https://github.com/oimlsmart/cnml.git
cd cnml
pnpm install
pnpm dev

The dev server runs at http://localhost:4321/cnml/.

Try the web app

The web app at /cnml/app provides browser-based tools for evaluation:

  1. Generate a signing key at /keys. The key is generated in your browser using WebCrypto, encrypted with a passphrase you choose, and stored in IndexedDB. It never leaves your machine.

  2. Create a certificate at /create. Pick an OIML Recommendation (R60 for load cells, R76 for weighing instruments, etc.), fill in the evaluation results, and sign the CNML XML.

  3. Verify a certificate at /verify. Drop a .cnml.xml file onto the verifier. The seven-check pipeline runs entirely in your browser.

Run the test vectors

The repository ships with 22 pre-signed test vectors (one per Recommendation). These exercise the full sign + verify pipeline:

pnpm vectors:gen      # regenerate the vectors
pnpm vectors:verify   # verify all 22 round-trip

pnpm vectors:gen      # regenerate the vectors
pnpm vectors:verify   # verify all 22 round-trip

Next steps