The data in health care applications are digitalized in order to improve security. By combining several well-designed cryptographic mechanisms and developing a key management scheme to facilitate the interoperation among these mechanisms, the risk of illegal distribution can be reduced. Even authorized person may hack the data. Therefore, this paper provides a split-key encryption technology and homomorphic key encryption in cloud. The noteworthy term isn't encrypting the data - it's protecting the encryption keys. Every time an application accesses a data store, it needs to use the encryption keys.