Abstract: Mobile grid is a class of distributed systems that autonomously engages sharing of resources and exchange of services to provide higher performance and utilization of the mobile device resources in a seamless, transparent, secure and efficient way. It allows sharing and co-ordinate use of diverse resources in dynamic, heterogeneous and distributed environment. Mobile grid focuses towards many issues like data management, resource management information management, power management and security management. Due to the combinationb of grid and mobile devices, it leads to many security issues like authentication, authorization, non-repudiation integrity, confidentiality and secure routing. Our main focus is to provide authentication and secure communication. In existing system, certificate authority is used for athrough digital certificates which is a trusted third party and has the responsibility of certificate generation and verification. If the CA is subverted, then the security of the entire system is lost. Normally RSA algorithm of 1024 bit key size is used which is computationally infeasible to perform the encryption which results in more power consumption and it is not suitable for mobile devices which are battery powered. In proposed system, a new architecture called Supervisory Host (SH) that helps in generating and distributing the Secure Service Certificates (SSC) is employed. Elliptic Curve Digital Signature Algorithm (ECDSA) of 168-bit, key size is used for generating digital signature which results in compact implementation and less heat generation. CHORD DHT (Distributed Hash Table) is used for secure and effective routing. Thus the combination of SH and ECDSA algorithm helps to improve the trust level in organizations.