Security of data in data communication has become an important issue over the years. Consequently, various encryption schemes have come up as a solution, thus making encryption play an important role in information security system. These encryption schemes use some algorithms to scramble data into unreadable text which can only be decoded or decrypted by those that possesses the associated key. These algorithms consume significant amount of computing resources such as CPU time and storage (memory and primary storage). This paper therefore performs comparative analysis of four symmetric key encryption algorithms; AES, DES, 3DES and Blowfish by considering four parameters, encryption time, decryption time, memory usages and number of output bytes. Experimental results using Data Security Model Analyser was used in analysing the effectiveness of each of these algorithms.