What are the levels of the non-repudiation factor (NP.a to NP.c) in identity proofing, and what is it for?
NP.a no data collected; NP.b a copy of an evidence document with physical features is made and stored at verification; NP.c biometric data (such as fingerprints or facial images) are collected and stored to document the applicant's presence. The goal is to be able to prove later that the applicant really was at the registration.
The questions: Can it be proven at a later time that an applicant was present at registration? Can the subject be prevented from denying that presence, and with it the issuance of an authenticator?
| Value | What is recorded |
|---|---|
| NP.a | Nothing |
| NP.b | A copy of an evidence document that contains physical features (e.g. a copy of the passport photo page) |
| NP.c | Biometric data captured at the time, such as fingerprints or a facial image |
Why this matters: imagine a dispute months later. A customer claims "I never opened this account, someone used my identity". With NP.a the provider has nothing. With NP.b it can show the copy of the ID that was presented, but not that the holder was the one presenting it. With NP.c it has a photo or fingerprint of the actual person at the counter, which can settle the question. The price is privacy: stored biometrics are sensitive personal data and need strong protection.
Go deeper:
Non-repudiation (Wikipedia) — the general concept of making an action impossible to deny later.