IAL2 (Identity Assurance Level 2) is the identity-proofing level defined in NIST Special Publication 800-63A at which an applicant's claimed identity is confirmed against evidence — typically a government-issued photo ID matched to a live selfie — rather than through knowledge-based questions alone.
Why it matters to a preparer
For remote Form 8879 signing, IRS guidance accepts identity verification performed at a NIST-defined assurance level such as IAL2 as an alternative to knowledge-based authentication (KBA); Publication 1345 points to NIST SP 800-63 for the standard. Where KBA can lock out a legitimate signer whose public-records history is thin, IAL2 verification checks something the signer physically holds — their ID — matched against their live face, which tends to be more reliable for the client even though it takes an extra minute at signing time.
For a client who has recently moved, has thin credit history, or otherwise struggles with out-of-wallet questions, IAL2 is often the smoother path to a completed signature rather than a support call. Because it doesn't depend on how much of a paper trail someone has left in credit and public records, it tends to hold up just as well for a taxpayer with a thin financial history as for one with decades of accounts on file.
How it works
The taxpayer photographs a government-issued photo ID (driver's license, state ID, or passport) and completes a live selfie or short video capture; a service meeting the IAL2 bar matches the two before the signature is treated as verified. NIST SP 800-63A is the standard that defines what evidence and matching process qualifies as IAL2 — it's a federal identity-assurance framework, not a tax-specific rule, which IRS guidance then references for the 8879 use case.
See our guide to e-signing Form 8879 remotely for where IAL2 fits alongside KBA and the in-person exception. Verification can often be selected per document or per client rather than fixed for every signer.