July 2, 2019

NIST 800-63-3 Digital Identity Guidelines – A Primer

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Archit Lohokare Chief Product Officer
NIST series post 1

The National Institute of Standards and Technology (NIST), in June 2017, published a new set of guidelines as part of their special publication 800-63-3 that provided technical requirements for federal agencies implementing digital identity services. These guidelines have been instrumental in helping me and many others in the Identity and Access Management space learn, think through, and build out product strategy for our product lines. I’ve had the privilege and good fortune to speak to many of Idaptive’s customers about these guidelines in the context of their identity and authentication assurance needs, and I’ve always been encouraged and inspired by the immense amount of interest and debate these guidelines generate. Also, I recently had the great privilege to speak to some incredibly smart folks at NIST about Idaptive and our technology, and it made me realize that it was time to put pen to paper and provide a quick perspective on these guidelines. This is part one of a 4-part blog series.

The 800-63-3 Digital Identity guidelines have expanded on a singular concept of level of assurance (LOA) for all electronic authentication of digital identities that was originally introduced in 800-63-2. The new guidelines are more specific to the business needs and use cases where digital identities are to be used. Very broadly, the new guidelines cover three processes, Identity Proofing, Digital Authentication and Federated Identity Management.


The Digital Identity, as NIST explains it

The digital identity is a unique representation of the physical subject, or individual (in Idaptive’s world, given our focus), in the online world, that is engaged in an online transaction. This transaction could be as simple as just logging into a single service, or as complex as performing an e-commerce transaction across multiple services or websites. The purpose of the digital identity is often limited to use in the context of the service alone and does not necessarily need include or need all the physical world attributes or information of the individual.


Identity Proofing, Digital Authentication and Federated Identity Management


NIST image 1

Figure: Digital Identity Model, Source: NIST Special Publication 800-63 Volume 3 Revision 3, Digital Identity Guidelines

The image above provides an excellent overview of the key processes digital identities participate in. CSP, in this diagram, refers to a Credential Service Provider that is responsible for performing the enrollment, identity proofing and issuance processes. The Verifier is responsible the service or the party that verifies the individual’s digital identity.

Enrollment and Identity Proofing is the process of assuring that an individual (or subject) is who they claim to be, and “IAL” (Identity Assurance Level) refers to the level of assurance (or “strength”) with which this assurance can be described. An example of proofing an individual would be to ask them questions about them that only they (hopefully) would know. Alternately, another example would be to ask them to submit a copy of their state issues Driver’s License, proving proof of possession of a state attested identity document.

Digital Authentication is the process of an individual attempting to access a service, and “AAL” (Authentication Assurance Level), similarly, is used to provide assurance that the individual accessing a service is possession of one or more authenticators associated with them. An example of this would be to send a one-time password to the individual’s registered phone via a notification or a text. Another example would be to ask the user to authenticate using their Personal Identity Verification, or PIV card.

Finally, Federated Identity management involves a user, authenticated by a third party Identity Provider (IdP), attempting to access a service (Service Provider) or a Relying Party (RP) via a token or an assertion that the IdP sends to the service, and “FAL” (Federated Assurance Level) refers to the strength of that assertion that is used to communicate authentication and attribute information to the RP. 800-63-3 is further broken down into 800-63-A which provides guidelines on Enrollment and Identity Proofing and covers Identity Assurance Levels, 800-63-B which provides guidelines on Authentication and Lifecycle Management and covers Authentication Assurance Levels and finally, 800-63-C which provides guidelines on Federation and Assertions, and covers Federated Assurance Levels. 


Levels of Assurance, at a glance

The NIST guidelines document provides an excellent summary of what constitutes Levels of Assurance for each of the three key processes mentioned above. Levels of Assurance for a process, for all practical purposes, are indicators of the “strength” of the identity and access management controls implemented as part of that process. Typically, they range from level 1 to level 3. Below is a series of tables that are included in the guideline document that provide the summaries.

Identity Assurance Levels

Identity Assurance Levels

Authentication Assurance Levels

Authentication Assurance Levels


Federated Assurance Levels

FAL levels


Each of these guidelines, by themselves, deserve a series of blogs, if not a whitepaper. To that end my next series of blogs on this topic will focus on providing additional color on 800-63-A, 800-63-B and 800-63-C, how organizations should go about adopting these guidelines and choosing what level of assurance they should ideally target, and how Idaptive can help with achieving high levels of assurance for 800-63-B and 800-63-C. Stay tuned!


NIST Series Part 1

NIST Series Part 2

NIST Series Part 3

NIST Series Part 4

Archit Lohokare

Archit headshot
Chief Product Officer

Archit Lohokare is Chief Product Officer at Idaptive, where he is responsible for product strategy, driving innovation, and bringing new products and services to market. He transitioned over to Idaptive as it was spun-out from Centrify, where—as Vice President of Product Management—he led the Identity-as-a-Service (IDaaS) and Unified Endpoint Management product portfolio. Prior to Centrify, Archit was Vice President of Products at Optymyze, where he led the product management team responsible for the company’s Sales Performance Management and Sales Platform-as-a-Service SaaS and PaaS solutions, securing a Leadership position in the first Gartner Magic Quadrant report on Sales Performance Management along the way. 

Earlier in his career, Archit led Symantec's Cloud Information Protection Security-as-a-Service offering, and IBM's Access Management product line, comprised of Web Access Management, Identity Federation, Enterprise Single Sign-On, and Risk-based Access and Entitlements Management products. Archit joined IBM through the acquisition of Encentuate, a leading Bay Area start-up in the security software space; as an early employee, he had the opportunity to contribute to its successful exit. 

Archit has an MBA from UC Berkeley-Haas School of Business, and a bachelor’s degree in Computer Engineering from NTU, Singapore, where he was awarded the SIA-NOL undergraduate scholarship by the Ministry of Education, Singapore.

Archit is an avid history buff, enjoys reading in his spare time and running breathlessly after his one-year-old, hyperactive son.


If Archit could have any Chameleon-like superpower, it would be the ability to change colors quickly and adapt. “Actually, it would be like the ability of our IAM solutions to adapt instantaneously to a customer’s environment and user behavior. Anomalous user access? A snap! Presto, change-o – like a chameleon from green to red in an instant, adapt to the change in user behavior and request user to assure their identities using multi-factor authentication...”