Identity proofing: tying an account to a real person

Identity proofing is the process of establishing, to a stated level of confidence, that a claimed identity belongs to a real person. NIST defines it as “the processes used to collect, validate, and verify information about a subject to establish assurance in the subject’s claimed identity.” Proofing happens at enrollment; it is different from signing in later, and it does not decide whether a person is eligible for a benefit or a ballot.

Definition

The NIST SP 800-63-4 and SP 800-63A-4 definition quoted above is the current federal standard.⁠¹ Older NIST and federal definitions describe proofing as “the process of providing sufficient information (e.g., identity history, credentials, documents) to establish an identity”.⁠¹ SP 800-63A-4 describes the purpose as “establishing a relationship between a subject” and a real-life person.⁠²

Proofing proceeds in three steps named in SP 800-63A-4:⁠²

• Resolution: distinguishing the person among all people (enough attributes to identify one individual).
• Validation: checking that the evidence presented (for example, a document) is genuine and accurate.
• Verification: confirming that the person presenting the evidence is the person it describes.

Origin and history

Federal identity proofing rules developed alongside online government services and personal identity verification cards. The current version, SP 800-63-4, “supersedes NIST Special Publication (SP) 800-63-3”.⁠³ and organizes assurance into three Identity Assurance Levels⁠³ SP 800-63A-4 summarizes them:⁠²

• IAL1: the process “supports the real-world existence of the claimed identity.”
• IAL2: “requires collecting additional evidence and more rigorous processes for validating evidence.”
• IAL3: “adds the requirements for a trained CSP representative.”

SP 800-63A-4 also names the settings in which proofing can occur: remote unattended (fully automated), remote attended (through “a secure video session”), and on-site attended (in a physical setting).⁠²

How identity proofing is used

Proofing is used wherever a service must be confident that an account belongs to a particular real person: tax filing, benefits, licensing. The level chosen depends on the harm a false identity could cause. NIST states plainly that proofing can inform decisions about benefits or services but “such determinations are outside of the scope of these guidelines”.⁠² Proofing tells a service who someone is; the service’s own rules decide what that person is entitled to.

In U.S. elections, a version of resolution and validation happens at registration. Federal law requires states to maintain a single statewide computerized voter list and generally requires a driver’s license number or “the last 4 digits of the applicant’s social security number” on registration applications for federal elections.⁠⁴ That is not NIST identity proofing; it is an election law process with its own rules, run by election officials.

Common confusions and neighboring terms

• Identity proofing vs. authentication. Proofing happens once, at enrollment. Authentication happens at each sign-in and only proves control of the account.
• Identity proofing vs. eligibility. A fully proofed person may still be ineligible to vote (for example, under 18 or not a citizen).
• Identity proofing vs. registration. Voter registration is the legal process of entering an eligible person on the roll. It uses identity information but is governed by election law.
• Identity proofing vs. identity verification. Verification is one of the three steps of proofing, not a synonym for the whole process.

How My Vote Forward uses the term

My Vote Forward does not perform identity proofing on its demo. Its accounts are authenticated with passkeys but never tied to a legal identity, and the framework says so directly in Identity and registration. Any future official use would depend on identity and eligibility processes run by responsible authorities, under law, with independent evaluation. No such arrangement exists. The privacy consequences of collecting identity evidence are discussed in Privacy.

Unresolved questions

• Could a civic participation system rely on proofing done by an existing authority without that authority learning what people express?
• How should remote proofing be designed for people whose documents or faces are poorly handled by automated checks?
• What level of proofing, if any, is proportionate for a system that publishes only aggregates?