In this paper, we discuss the recent ESG’s development and implementation efforts concerning its authentication infrastructure. ESG’s requirements are to make the user’s logon-experience as easy as possible, and to facilitate the integration of the security services and the Grid components for both the developers and system administrators. To meet that goal, we leverage existing primary authentication mechanisms, deploy a “lightweight” but secure OpenID WebSSO, deploy a "lightweight” X.509-PKI, and use autoprovisioning to ease the burden of security configuration management. We’re close to finalizing the associated development and deployment. Categories and Subject Descriptors K.6.5 [Management of Computing and Information Systems]: Security and Protection --- Authentication General Terms Management, Security, Human Factors. Keywords Authentication, Authorization, OpenID, PKI, SLCS, SAML, ESG.