Nowadays hi-tech secure products need more services and more security. Furthermore the corresponding market is now oriented towards more flexibility. Thus, this book presents implementation of the Advanced Encryption standard (Rijndael) and compares how it performs on different platforms. In this book, the Advanced Encryption Algorithm is implemented for ARM based platforms. Although the AES is fully defined in terms of functionality, it requires best exploitation of architectural parameters in order to reach the optimum performance on specific architectures. Our book concentrates on ARM cores widely used in the embedded industry.