Web Services are an XML based technology that allow applications to communicate with each other across disparate systems. Web Services are becoming the de facto standard that enable inter operability between heterogeneous processes and systems. AliEn2 is a grid environment based on web services. The AliEn2 services can be divided in three categories: Central services, deployed once per organization; Site services, deployed on each of the participating centers; Job Agents running on the worker nodes automatically. A security model to protect these services is essential for the whole system.

Current implementations of web server, such as Apache, are not suitable to be used within the grid environment. Apache with the mod_ssl and OpenSSL only supports the X.509 certificates. But in the grid environment, the common credential is the proxy certificate for the purpose of providing restricted proxy and delegation. An Authentication framework was taken for AliEn2 web services to add the ability to accept X.509 certificates and proxy certificates from client-side to Apache Web Server. The authentication framework could also allow the generation of access control policies to limit access to the AliEn2 web services.