Abstract: In this paper we give a survey of third party based model for security in cloud computing environment. Cloud Computing is becoming the heart or the central theme for all sort of computing. Cloud is a remote place, at which user can upload data, can download data, can do processing of data, etc. Cloud provides space, computing power, platform and many more services on rent. This paper presents a brief introduction to the concept of clouds & its services. This paper also presents the issues related to the security of data in cloud environment. A few modern attribute based encryption models for the data security have been discussed.

Keywords: cloud security, third party based model, encryption, decryption method, key generation.