Argus  is an authorisation framework developed in EGEE-III and the primary authorisation service used in the EGI infrastructure. It is based on XACML2, consisting of separate PAP, PDP and PEP components. The PEP is split into a separate PEP-server and PEP-client part. The PEP-server and client communicate with each other via a proprietary binary protocol (`Hessian’). The Policy Administration Point (PAP) provides the tools to author authorisation policies, organise them in the local repository and configure policy distribution among remote PAPs. The Policy Decision Point (PDP) implements the authorisation engine, and is responsible for the evaluation of the authorisation requests against the XACML policies it retrieves from the PAP. The Policy Enforcement Point Server (PEP Server) ensures the integrity and consistency of the authorisation requests received from the PEP clients. Lightweight PEP client libraries (Java and C) are also provided to ease the integration and interoperability with other EMI services or components.