COMMUNICATION ENCRYPTION METHOD AND DEVICE

An encryption method and device employing a modified low-resource AES algorithm. The algorithm in one embodiment has a 128-bit key and a 16-bit data type, along with optimization functions including function inlining, memory move reduction via multiple transformations on a given state during a given iteration of a main loop of the algorithm, pointer-based accessing of the state from a transformation function, and a global key schedule. Another embodiment of the invention is a low-power secure communication device comprising a ZigBee-compliant transceiver having a maximum over-the-air data rate of 250 kbps, and a 16-bit RISC encryption processor configured to implement an AES algorithm adapted to encrypt data at a faster rate than 250 kbps. The AES algorithm only requires about 5000 bytes of ROM and about 250 bytes of RAM. The disclosed implementation of AES in a high-level language (C in this case) is believed to be the first software-based solution for 16-bit microcontrollers capable of matching the communication rate of 250 kbps specified by the Zigbee protocol, while also minimizing RAM and ROM usage.