The analysis of the impact of mobile computing on the various services shows how the mobile computing has changed each service. As mobile computing has become more popular over the past decade, it has been under continuous development with advances in hardware, software, and network. Mobile computing has various applications in our everyday life. The convergence of Internet and mobile computing enables personalized access to online services anywhere and anytime. Entities (e.g., users, services) have to authenticate themselves to service providers in order to use their services. An entity provides personally identifiable information that uniquely identifies it to a Service Provider. Due to the rapid spread of smart phones and social network service, the use of Interne applications has increased and their need for bandwidth has begun to exceed the capacity of 3G networks. This has caused a reduction in speed and service quality. The increase in mobile network users has caused identity management problems for mobile service providers. Therefore, in this paper, proposed system is designed to overcome this problem Improved Identity Management protocol is used to breaks up loads, which are allowed by the existing Identity Management 3G protocol's mutual authentication via mobile operator process, by sending some parts to an Internet application service provider to enhance mobile and ID management at the service provider and by reducing the network and process loads from information handling and packet transmission. The proposed system used the RC-5 algorithm to increase the speed and security in mobile cloud computing providing private key and public key with existing method and it is fulfilling the needs of cloud users and Providers.