This Application Note covers four encryption algorithms: AES, XTEA, SKIPJACK ® and a simple encryption algorithm using a pseudo-random binary sequence generator. The science of cryptography dates back to ancient Egypt. In today’s era of informa- tion technology where data is widely accessible, sensitive material, especially electronic data, needs to be encrypted for the user’s protection. For example, a network-based card entry door system that logs the persons who have entered the building may be suscep- tible to an attack where the user information can be stolen or manipulated by sniffing or spoofing the link between the processor and the memory storage device. If the information is encrypted first, it has a better chance of remaining secure. Many encryption algorithms provide protection against someone reading the hidden data, as well as providing protection against tampering. In most algorithms, the decryption process will cause the entire block of information to be destroyed if there is a single bit error in the block prior to decryption. AN953 Data Encryption Routines for the PIC18 Author: David Flowers ENCRYPTION MODULE OVERVIEW Microchip Technology Inc. Four algorithms to choose from, each with their own benefits INTRODUCTION Advanced Encryption Standard (AES) This Application Note covers four encryption - Modules available in C, Assembly and algorithms: AES, XTEA, SKIPJACK and a simple Assembly written for C encryption algorithm using a pseudo-random ……