This thesis presents the design, implementation, and evaluation of EAP-SPID, a novel authentication method that integrates the Italian digital identity system SPID into the IEEE 802.1X framework. The key aim of this work is to overcome the weaknesses of traditional network access control by leveraging federated identity management so that users can authenticate with their federated credentials in enterprise and public network environments. The proposed solution extends the Extensible Authentication Protocol (EAP) by introducing EAP-SPID, which exploits SPID’s SAML-based infrastructure, but at the same time operates under the requirements of 802.1X and the EAP framework to maintain compatibility with existing 802.1X deployments.