31 Lee, R B Rivest, R L Robshaw, M J B Shi, Z J Yin, Y L 2004 Nadia Nedjah Luiza de Macedo Mourelle Book chapter in Nadia Nedjah and Luiza de Macedo Mourelle eds., Embedded Cryptographic Hardware: Design and Security New York Nova Science Publisher, ISBN: 1-59454-145-0, Chapter 13 219-236 http://books.google.com/books?id=1Npt_Gj7nJIC&pg=PA19&lpg=PA19&dq=PAX:+A+Datapath-Scalable+Minimalist+Cryptographic+Processor+for&source=bl&ots=At_exM0b76&sig=Kkvh1BvA3mfnbwpU4_kuEgAqjR0&hl=en&sa=X&oi=book_result&resnum=1&ct=result#PPR9,M1 http://palms.ee.princeton.edu/PALMSopen/lee04permutation_book.pdf