3.3.3 Initial Assurance Level Selection

Before selecting an initial assurance level, RPs must determine whether identity proofing is needed for the users of their online services. Identity proofing is not required if the online service does not need any personal information to execute digital transactions. If personal information is needed, the RP must determine whether validated attributes are required or if self-asserted attributes are acceptable. The system may also be able to operate without identity proofing if the potential harms from accepting self-asserted attributes are insignificant. In such cases, the identity proofing processes described in [SP800-63A] are not applicable to the system.

If the online service does require identity proofing, an initial IAL is selected through a simple mapping process:

The organization SHALL document whether identity proofing is required for their application and, if it is, SHALL select an initial IAL for each user group based on the effective impact level determination from Sec. 3.2.4.

The IAL reflects the level of assurance that an applicant holds the claimed real-life identity. The initial selection assumes that higher potential impacts of failures in the identity proofing process should be mitigated by higher assurance processes.

Authentication is needed for online services that offer access to personal information, protected information, or subscriber accounts. Organizations should consider the legal, regulatory, or policy requirements that govern online services when making decisions regarding the application of authentication assurance levels and authentication mechanisms. For example, [EO13681] states that “all organizations making personal data accessible to citizens through digital applications require the use of multiple factors of authentication,” which requires a minimum selection of AAL2 for applications that meet those criteria.

If the online service requires authentication to be implemented, an initial AAL is selected through a simple mapping process:

The organization SHALL document whether authentication is needed for their online service and, if it is, SHALL select an initial AAL for each user group based on the effective impact level determination from Sec. 3.2.4.

The AAL reflects the level of assurance that the claimant is the same individual to whom the authenticator was registered. The initial selection assumes that higher potential impacts of failures in the authentication process should be mitigated by higher assurance processes.

Identity federation brings many benefits, including a convenient customer experience that avoids redundant, costly, and often time-consuming identity processes. The benefits of federation through a general-purpose IdP model or a subscriber-controlled wallet model are covered in Sec. 5 of [SP800-63C]. However, not all online services will be able to make use of federation, whether for risk-based reasons or due to legal or regulatory requirements. Consistent with [M-19-17], federal agencies that operate online services SHOULD implement federation as an option for user access.

If the online service implements identity federation, an initial FAL is selected through a simple mapping process:

The organization SHALL document whether federation will be used for their online service and, if it is, SHALL select an initial FAL for each user group based on the effective impact level determination from Sec. 3.2.4.

For online services that are assessed to be high impact, organizations SHALL conduct a further assessment to evaluate the risk of a compromised IdP to determine whether FAL2 or FAL3 is more appropriate for their use case. Considerations SHOULD include the type of data being accessed, the location of the IdP (e.g., whether the IdP is internal or external to their enterprise boundary), and the availability of bound authenticators or holder-of-key capabilities.

The FAL reflects the level of assurance in identity assertions that convey the results of authentication processes and relevant identity information to RP online services. The preliminary selection assumes that higher potential impacts of failures in federated identity architectures should be mitigated by higher assurance processes.