Abstract: Cloud computing is becoming a popular tool for storing data both by individuals and corporate sectors. The cloud provides many services which are accessible and economical for its users over the Globe. The main concern of the data storage in the cloud is its security. Many security attacks can happen when transferring and keeping the data over the network. This paper studies about the various network security issues and its solutions. Cryptography plays an important role in the security solution of cloud data. The paper discuss about DES, AES, and BLOWFISH to find the faster Cryptographic algorithm.

Keywords: Security, passive and active attacks, cryptography, symmetric and asymmetric encryption, DES, AES, RSA, BLOWFISH, CryptDB.