Apparatus and methods are provided for protecting network resources, particularly in association with automatic provisioning of new client devices. A global PKI (Public Key Infrastructure) scheme is rooted at a globally available server. Roots of PKIs for individual organizations also reside at this server or another globally available resource. To enable access to an organization's network, one or more authenticators are deployed, which may be co-located with access points or other network components. After a client device enabler (CDE) and an authenticator perform mutual authentication with certificates issued within the global PKI, the CDE is used to provision a new client device for the organization. After the client is provisioned, it and an authenticator use certificates issued within the per-organization PKI to allow the client access to the network.