Abstract
Wireless sensor networks are usually used in military applications, such as gathering enemies’ information. Therefore, the protection of data transfers between nodes from enemies is critical. It is necessary to encrypt the information before the information is transmitted. We implement an Encryption/Decryption chip that is suitable for applications in wireless sensor network nodes. The most important issues are the power consumption and gate count of the circuit because resources and power supply are usually limited in wireless sensor nodes. We create modified AES algorithm based on AES. We combine SubBytes () with multiplications of MixColumns () by means of three different tables to reduce gate counts. In addition, we implement InvSubBytes () and SubWord () with composite field calculation because the sharing of GF(24)2 inverter leads to lower gate count. The total gate count of our circuit is about 45.5K. Besides, since the most power-consuming parts of modified AES are S-box and Inverse S-box we use 3-stage AND-XOR architecture in the designs of S-box and Inverse S-box to get lower power dissipation. The power consumption of our circuit is about 42.53mW.