A Centralized Authentication & Authorization (CAA) system that prevents unauthorized access to client data using a secure global hashtable residing in the application server in a web services environment. CAA comprises a Service Request Filter (SRF) and Security Program (SP). The SRF intercepts service requests, extracts the service client's identifier from a digital certificate attached to the request, and stores the identifier in memory accessible to service providers. The client identifier is secured by the SP using a key unique to the client identifier. When the web services manager requests the client identifier, the web services manager must present the key to the SP in order to access the client identifier. Thus, the present invention prevents a malicious user from attempting to obtain sensitive data within the application server once the malicious user has gained access past the firewall.