112 Security and authentication are an increasingly essential part of web development. PKI enabled systems depend on digital certificates, electronic credentials issued by a certificate authority (CA), to establish identity and trust. Many government agencies and corporations are adopting PKI based security often implemented as smart card based authentication. The smart card's security comes from two things, one you know and one you own. This will be a guide towards implementing a PKI certificate authentication system via Apache and MapServer to limit map requests to valid authenticated users. FOSS4G2006 - Free And Open Source Software for Geoinformatics Session 2 : SDI-OGC-Security Michael Smith michael.smith@erdc.usace.army.mil Michael Smith michael.smith@erdc.usace.army.mil <MaKaC.conference.ContributionType object at 0xb3c102ec> SDI-SECURITY