Wireless transmission of data is prone to lot of attacks by intruder compared to wired networks. There is a need to make the data transmission more secure and safe. In this paper, we focus on generating symmetric key for secure data transmission using enhanced AES-128Algorithm based on Secret Key Cryptography technique. AES is highly efficient, highly secure and not complex compared to other algorithms. Here we are concerned in reducing the time required for generating the secret key using AES Algorithm to improve the network performance. In our paper, we analyze the performance of the proposed system by comparing the metrics of key generation with the existing AES based system. © Research India Publications.