Identity: the attributes that describe a particular person

An identity is the set of attributes that describes a particular person within a given context. NIST’s digital identity guidelines define a digital identity as “an attribute or set of attributes that uniquely describes a subject within a given context.” Having an identity, proving control of an account, and being legally eligible to vote are three different things, and My Vote Forward keeps them separate.

Definition

NIST’s Computer Security Resource Center glossary lists several definitions of identity drawn from different standards. The one used in the current digital identity guidelines, NIST SP 800-63-4, defines digital identity as “an attribute or set of attributes that uniquely describes a subject within a given context”.⁠¹ Older federal standards for personal identity verification define identity as “the set of physical and behavioral characteristics by which an individual is uniquely recognizable”.⁠¹ NIST SP 800-63-4 adds that “a digital identity is always unique in the context of an online service”.⁠²

The phrase “within a given context” carries the meaning. A person may have one identity at a bank, another at a library, and a third at an election office, each built from different attributes (an account number, a card number, a voter registration record). None of them is the person in every sense; each is a description good enough for one purpose.

Origin and history

Digital identity became a formal standards topic as governments moved services online. NIST’s guidelines organize the problem into three functions, each with its own assurance level. SP 800-63-4 uses Identity Assurance Level (IAL), Authentication Assurance Level (AAL), and Federation Assurance Level (FAL), and states that “each xAL has three assurance levels”.⁠² SP 800-63-4 “supersedes NIST Special Publication (SP) 800-63-3”.⁠² The split itself is the lesson: knowing who someone is (identity proofing), confirming that the person signing in controls the account (authentication), and passing identity information between services (federation) are distinct.

How identity is established and used

In practice, an identity is created by enrollment. Under SP 800-63A-4, identity proofing is “the process of establishing a relationship between a subject” and a real-life person, through steps of resolution, validation, and verification.⁠³ After enrollment, the person is a subscriber with an account, and later sign-ins are authentications against that account.

Identity is then used to make decisions, but NIST is explicit that the decision is separate. SP 800-63A-4 says identity proofing can inform decisions about benefits or services, but “such determinations are outside of the scope of these guidelines”.⁠³ In elections, the decision is eligibility, set by law: citizenship, age, residence, and other requirements. The person deciding is an election official, not an identity provider.

Common confusions and neighboring terms

• Identity vs. authentication. Authentication proves control of an account bound to an identity. It does not establish the identity in the first place.
• Identity vs. identity proofing. Proofing is the process that establishes, to a stated level of confidence, that a claimed identity belongs to a real person.
• Identity vs. eligibility. Knowing exactly who someone is does not tell you whether they may vote in a particular election.
• Identity vs. anonymity. A system can verify identity at entry and still keep later actions unlinkable to that identity. That is the logic of the secret ballot. See Secrecy.
• Identity vs. biometric. A fingerprint or face is an attribute used to recognize a person; it is not the identity, and it does not prove eligibility.

How My Vote Forward uses the term

My Vote Forward uses “identity” in the NIST sense and keeps it apart from eligibility and from the content of anything a person expresses. The framework’s position, set out in Identity and registration, is that an account on its demo is not a voter registration, and that any future official use would rely on election authorities for eligibility. Its demo uses passkeys for sign-in, which authenticate an account but do not establish legal identity. See Passkey.

Unresolved questions

• What is the least identity information a civic participation system needs to resist duplicate accounts while protecting privacy?
• If a future system relied on government identity proofing, who would hold the link between a person’s identity and their participation, and how would it be audited?
• How should people without standard documents be included without lowering assurance for everyone?