Certificate register
talas.fr · the public list of measurement certificates issued
Every microphone that leaves the workshop is measured, and each measurement produces a certificate. This page lists those certificates and publishes the key that proves a certificate really came from us — without having to take our word for it.
A certificate proves who issued it and that nothing has changed since. It doesn't prove the measurement is right. Mixing the two up is the worst thing a certificate could do: accuracy comes from the measurement protocol, described in the certificate itself, not from the signature.
1What this register is for
A signature stops anyone forging a certificate without the private key. It doesn't stop two other tricks: issuing two conflicting certificates for the same unit and only showing the flattering one, and backdating — producing a document today that claims to be from last year.
Publishing the list closes both doors. It's append-only: a published line is never removed, and its history is that of a version-controlled repository. A repeated measurement produces a new certificate with its own identifier, and both stay on the list.
2Certificates issued
3Verifying a certificate
All three checks work offline, using the certificate you received and the public key below. None of them goes through our servers: a check that needs the issuer's cooperation doesn't check the issuer.
| Integrity | does the printed fingerprint match the certified facts? talas-analyze cert-verify certificate.json |
|---|---|
| Issuer | is the signature ours? openssl pkeyutl -verify -pubin -inkey cle-publique.pem -rawin -in empreinte -sigfile signature |
| Existence | is the identifier in the list above, and since when? |
Our Ed25519 signing public key, exactly as our vault hands it out: cle-publique.pem. The private key never leaves the vault: the workshop sends it a fingerprint and gets a signature back.
4What isn't published here
The register holds the serial number, the certificate's identifier, its fingerprint and its dates. It holds no measurements, no recordings, and not the name of whoever owns the unit. The measurements are in the certificate that comes with the microphone.
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