Trustswiftly NIST 800-63-4 IAL3 Benefits for Businesses The Identity Proofing (IAL3) process introduced with NIST 800-63-4 requires more rigorous evidence collection to validate and link claimed identities to evidence collected, which also limits highly scalable attacks while offering additional protections against synthetic identity fraud. Interested readers are strongly recommended to refer to its companion volumes [SP800-63A] and [SP800-63B] for normative guidelines and requirements at each assurance level.