Abstract—There are various technical issues inside a distributed system and authentication issue is one of them. OpenID is a decentralized single sign-on authentication system on internet. With more and more applications are authenticated through OpenID mechanism, an OpenID based authentication architecture for a distributed system environment is designed in this paper. The proposed architecture emphasizes the advantage of OpenID deployed in a decentralized environment composed of system nodes. Besides, the proposed architecture supports the existing database authentication like AD or LDAP which are popular and widely used in enterprise. The detail illustration about the architecture that describes the network topology for authentication is given in the last paragraph. The proposed mechanism can solve the authentication issue in a distributed system.