Company ABC was formed by combining numerous companies which all had multiple databases, web portals, and cloud data sets. Each data store had a unique set of custom developed authentication…

Attestation is a process for verifying hardware or software integrity, not a mechanism for combining or federating disparate user authentication systems.

PKI requires deploying or expanding a certificate authority infrastructure and potentially re-issuing credentials to all users, resulting in significant upfront costs.

Biometrics requires purchasing and deploying hardware sensors across all locations and building new enrollment databases, incurring substantial upfront investment.

Federated identity (using standards like SAML or OAuth/OIDC) establishes trust relationships between existing identity providers without requiring custom development or replacement of the underlying authentication systems, making it the lowest-cost approach to combining disparate mechanisms already in place across the merged entity.