Now a day’s most of the users are using wireless communication for fast sending and receiving the mails in less time and in less cost. The main issue in this way of communication is information hacking. Here a crypto device with low complexity and high security is designed by using Advanced Encryption Standard Algorithm along with Built in Self-Test technique. This paper provides the complete step by step implementation of Advanced Encryption Technique, i.e. encrypting and decrypting 128 bit data using the AES by providing enhanced reliability and security. Extra cost in terms of area is very low compared to other techniques. Because only one AES core will be originally embedded in the system. This reduces the reduction of test cost will lead to the reduction of overall production cost & 100% security of data.