Abstract: Grid computing is a group of computer organizations from various fields which have joined together to achieve a common interest. A grid security issue is one of the main problem to grid computing. Security in terms of an authentication is a major issue in the Heterogeneous Grid System. Authentication is the process of confirming the identity of a person or a software program. In this proposed methodology, secure group communication is ensured to authenticated users by an effective key distribution using Cyclic Shift Transposition Algorithm (CSTA) which uses multiple key distributions during file or data transfer in a Grid System. In addition, Hash function incorporates authentication of users and resources in a grid environment. CSTA Algorithm when compared with other authentication algorithms like RSA, DES and AES, better results have been proven in terms of security and authentication.