Zero trust is a security model in which no user, device or request is trusted because of its network location. Every access decision is made from identity, device health and context, and re-checked continuously.
Field guide
Map every authenticator you use to NIST’s assurance levels, identify the restricted ones (SMS and voice codes), and for each restricted authenticator document a risk assessment, user notice, a non-restricted alternative and a migration plan. Add a phishing-resistant option such as passkeys, which Revision 4 accepts at AAL2.
Buyer’s guide
Phishing-resistant MFA is authentication that a fake site or man-in-the-middle can’t capture and replay, because the credential is cryptographically bound to the real site. FIDO2 passkeys and hardware security keys are the common examples, and CISA also counts PKI-based smart cards. SMS codes, authenticator-app codes and simple push approvals are not phishing-resistant.