Fast Implementation of AES on Mobile Devices

The Advanced Encryption Standard (AES) became the standard for encryption to protect the sensitive information. With the increasing use of portable and wireless devices and demanding information security needs in embedded systems, prompted efforts to find fast software based implementation of AES encryption/decryption capable of running on resource constrained environment in terms of processor speed, code space, energy usage and in particular those portable devices that have 32-bits ARM processor. ARM processor are most common for use in embedded industry. In this paper we propose an implementation of AES with minimum number of look-up tables in high level language C by performing a series of optimizations and their effects to enhance time performances that leads to our final implementation achieving speed of 323 mu s to encrypt 128-bits block of plain text. We develop experiments by making the reference implementation, as known from the technical literature, optimized first for the 32-bits ARM based platforms and then compared with our final implementation. We analyze speed of AES, the leading symmetric block cipher on ARM processor and shows that our implementation outperforms the reference implementation by more than 3 times. The simulation results of our optimized implementation with the other reference implementation are compared and presented.