The Difference Between Identity Assurance Levels 2 and 3

It’s been years since I talked about Identity Assurance Levels (IALs) in any detail, but I wanted to delve into two of the levels and see when IAL3 is necessary, and when it is not.

But first, a review

If the term “identity assurance level” is new to you, let me reprint what they are. This is taken from my December 3, 2020 post on identity assurance levels and digital identity.

The U.S. National Institute of Standards and Technology has defined “identity assurance levels” (IALs) that can be used when dealing with digital identities. It’s helpful to review how NIST has defined the IALs.

Assurance in a subscriber’s identity is described using one of three IALs:

IAL1: There is no requirement to link the applicant to a specific real-life identity. Any attributes provided in conjunction with the subject’s activities are self-asserted or should be treated as self-asserted (including attributes a [Credential Service Provider] CSP asserts to an [Relying Party] RP). Self-asserted attributes are neither validated nor verified.

IAL2: Evidence supports the real-world existence of the claimed identity and verifies that the applicant is appropriately associated with this real-world identity. IAL2 introduces the need for either remote or physically-present identity proofing. Attributes could be asserted by CSPs to RPs in support of pseudonymous identity with verified attributes. A CSP that supports IAL2 can support IAL1 transactions if the user consents.

IAL3: Physical presence is required for identity proofing. Identifying attributes must be verified by an authorized and trained CSP representative. As with IAL2, attributes could be asserted by CSPs to RPs in support of pseudonymous identity with verified attributes. A CSP that supports IAL3 can support IAL1 and IAL2 identity attributes if the user consents.

For purposes of this post, IAL1 is (if I may use a technical term) a nothingburger. It may be good enough for a Gmail account, but these days even social media accounts are more likely to require IAL2.

And it’s worthwhile to mention (as I did before) that in practice, IAL3 may not require physical presence.

IAL3: In-person or supervised-remote identity proofing is required.

From https://id4d.worldbank.org/guide/levels-assurance-loas

So what’s the practical difference between IAL2 and IAL3?

If we ignore IAL1 and concentrate on IAL2 and IAL3, we can see one difference between the two. IAL2 allows remote, unsupervised identity proofing, while IAL3 requires (in practice) that any remote identity proofing is supervised.

Much of my time at my previous employer Incode Technologies involved unsupervised remote identity proofing (IAL2). For example, if a woman wants to set up an account at a casino, she can complete the onboarding process to set up the account on her phone, without anyone from the casino being present to make sure she wasn’t faking her face or her ID. (Fraud detection is the “technologies” part of Incode Technologies, and that’s how they make sure she isn’t faking.)

But what if you need supervised remote identity proofing for legal or other reasons? Another company called NextgenID offers this.

But is this good enough? Yes it is, according to Nextgen.

SRIP provides remote supervision of in-person proofing using NextgenID’s Identity Stations, an all-in-one system designed to securely perform all enrollment processes and workflow requirements. The station facilitates the complete and accurate capture at IAL levels 1, 2 and 3 of all required personal identity documentations and includes a full complement of biometric capture support for face, fingerprint, and iris.

From https://www.nextgenid.com/markets-srip.php

Now there are some other differences between IAL2 and IAL3 in terms of the proofing, so NIST came up with a handy dandy chart that allows you to decide which IAL level you need.

When deciding between IAL2 and IAL3, question 3 in the table above is the most critical. NIST explains the purpose of question 3:

At this point, the agency understands that some level of proofing is required. Step 3 is intended to look at the potential impacts of an identity proofing failure to determine if IAL2 or IAL3 is the most appropriate selection. The primary identity proofing failure an agency may encounter is accepting a falsified identity as true, therefore providing a service or benefit to the wrong or ineligible person. In addition, proofing, when not required, or collecting more information than needed is a risk in and of itself. Hence, obtaining verified attribute information when not needed is also considered an identity proofing failure. This step should identify if the agency answered Step 1 and 2 incorrectly, realizing they do not need personal information to deliver the service. Risk should be considered from the perspective of the organization and to the user, since one may not be negatively impacted while the other could be significantly harmed. Agency risk management processes should commence with this step.

From https://pages.nist.gov/800-63-3/sp800-63-3.html#sec6

Even with the complexity of the flowchart, some determinations can be pretty simple. For example, if any of the six risks listed under question 3 are determined to be “high,” then you must use IAL3.

But the whole exercise is a lot to work through, and you need to work through it yourself. When I pasted the PNG file for the flowchart above into this blog post, I noticed that the filename is “IAL_CYOA.png.” And we all know what “CYOA” means.

But if you do the work, you’ll be better informed on the procedures you need to use to verify the identities of people.

One footnote: although NIST is a U.S. organization, its identity assurance levels (including IAL2 and IAL3) are used worldwide, including by the World Bank. So everyone should be familiar with them.