Abstract: Cloud computing provides convey of computing services such as networking, storage, databases, servers, databases, software, analytics and Online Internet . Cloud computing as a favor can transform and attract Information technology services. Now days, security of data become a large concern to insure various aspect like integrity, confidentiality, authentication etc. Cryptography techniques are used for this purpose. It plays a major role in protecting the data in those applications which are running in a network environment. To increase data security cryptography techniques also used on cloud because cloud computing provides secure transmission of data. On cloud, various computing task or programs can be run at a time. Cloud computing provides an illusion to the customers of using infinite computing resources that are available from anywhere, anytime, on demand.

Keywords: Cryptography, Cloud computing, RAS, DES, Ciphertext.