Green Cryptography: Cleaner Engineering through Recycling, Part 2
Justin Troutman, Vincent Rijmen · IEEE Security & Privacy · 2009
In part 1, we introduced "green cryptography" as a recycling-based paradigm for building mature (secure) and minimalist (simple) cryptographic implementations, using the AES (Advanced Encryption Standard) as our building block. We established that the AES is the poster child for green cryptography, because, as a standard, it receives more cryptanalytical attention than any other block cipher, thus "earning its bones." That, and it can be used with modes of operation for meeting the strongest notions of confidentiality and integrity. In part 2, we further defend our selection of the AES as a prime candidate for recycling, by looking at its underlying design strategy—the wide trail strategy—in the context of security margins—an often misunderstood metric for comparing block ciphers. We show that it's not always as easy as who has the most rounds; it's what's happening inside the round.