Cloud data storage are logical pools containing physical storages on multiple servers in different locations. All over the world, organizations and individuals are leveraging the storage of their confidential data to cloud data storages to reduce cost and enjoy the numerous benefits the cloud has to offer. Nonetheless, there are several security risks associated with outsourcing data to cloud data storages and the most concerning among these risks is the breach of data confidentiality. Data confidentiality is crucial in cloud data storages as the impact risk of a data breach can be catastrophic. Encryption is the best way to ensure data confidentiality and that, data is protected from unauthorized disclosure. The two most important features of encryption algorithms are the guarantee of security without any vulnerabilities (strength of encryption) and the efficiency (performance) of the algorithm. This paper presents a survey of popular encryption algorithms (Triple DES, AES, Blowfish and RSA) and their performance comparison report by simulating the selected encryption algorithms with a classification framework. Rivest-Shamir-Adleman (RSA) Encryption AlgorithmRSA was designed in 1978 by Ron Rivest, Adi Shamir, and Leonard Adleman. For key exchange, digital signatures or information block encryption, it is one of the best-recognized public-key cryptosystems. RSA uses an encryption block of variable size and a key of variable size. It is a number-theory based asymmetric (public key) cryptosystem. It generates public and private keys using two prime numbers. For encryption and decryption purposes, these two distinct keys are used. The sender encrypts the message using the public key and the receiver can decrypt it using his own private key when the message is transmitted to the receiver. Figure 1 below depicts the RSA multiple blocks process.