Today is the era of Internet and networks applications. So the Information Security has been very important issue in data communication. Any loss to information can prove to be great loss to the organization. Encryption has come up as a solution, and plays a vital role in information security system. Many techniques are needed to protect the shared data. The present work focus on cryptography to secure the data while transmitting in the network. First the data which is to be transmitted from sender to receiver in the network must be encrypted using the encryption algorithms. Secondly, by using decryption techniques the receiver can view the original data. This paper provides a comparison between five most common and used symmetric and asymmetric key algorithms: DES, 3DES, AES, RSA and MD5 algorithms and comparison has made based on their performance and time of encryption and decryption, block size, key size, and encryption/decryption time, in the form of throughput.