In recent years, due to the appealing features of cloud computing, large amount of data have been stored in the cloud. Although cloud based services offer many advantages, privacy and security of the sensitive data is a big concern. Medical and healthcare are private and sensitive information that are protected by law in many countries. In healthcare system all the medical transmission must be done high security. Now days corporate healthcare system depends on wireless communication, it is challenging issue to keep data secure without affecting the performance .Key management is a primary security service for group communication. For the secure key distribution of the key ,more encryption and decryption is involved which affects the performance the wireless communication. To achieve efficiency without compromising the security a polynomial based multicast unicast key distribution approach is used in proposed system. The Proposed scheme is compared with the existing centralized ,decentralized and distributed key management scheme and the performance is analyzed with communication ,computation and storage cost.