Know Your Device (KYD)
Definition. Know Your Device is Noxtica’s device-intelligence layer. It reads the many small, inert signals a browser naturally produces and condenses them into three durable artifacts: a stable, tamper-resistant fingerprint, a persistent device ID that follows a device across sessions, and a calibrated risk score.
A real device leaves a coherent picture across visits. A spoofed or automated one leaves contradictions. KYD is the part of Noxtica that builds that picture and notices when it doesn’t hold together.
How Noxtica does it
The collector runs inside the Sealed Runtime, a tamper-resistant runtime that gathers signals on the device and seals them so nothing can be quietly rewritten after collection. From those signals KYD produces:
- A stable fingerprint — the same browser produces the same fingerprint across sessions, so you recognize a returning device without storing raw values. What’s persisted is a scrambled, one-way summary, never the original signals.
- A persistent device ID — a durable handle for a device, so risk history and recognition survive across visits.
- A risk score — a 0-100 score and a plain-language tier, derived from how consistent the signals are with each other and with the wider population.
The score is a calibrated read, not a verdict. It comes with the reasons behind it so your team can act with context. KYD is operator-tuned: you set the thresholds, and the score never decides on your behalf.
Where it fits
KYD is the device half of the Intelligence pillar. It pairs with Know Your Agent (which governs which agents you trust) and Browser Intelligence (the signal categories the Sealed Runtime collects). The score KYD produces is what the Browser Security layer and the risk-action engine act on.
Read deeper
- Detection signals — the 30+ browser probes, the entropy each contributes, and the scoring weights behind the fingerprint.
- Browser runtime — what the Sealed Runtime collector does at collection time.
- Why calibration, not verdicts — why the score is a read, not a yes/no answer.
- Browser Intelligence — the signal categories that feed KYD.