During the recent times, with the tremendous growth of digital data communication over computer network, information content security becomes a prime concern. Internet itself allows many security threats and those can easily corrupt the transferred data over network. Cryptography plays an important role by providing security for digital transmission of data over such insecure network. Cryptographic protocols scramble data into unreadable text which can be only read or decrypted by those possesses the associated key. The Advanced Encryption Standard (AES) is symmetric key algorithm which provides higher security with higher encryption speed and throughput but still modifications are going on to improve its performance. In this paper we survey and analyze several modifications on AES encryption techniques on different parameters and compare their performance with conventional AES.