Abstract:

The new lightweight block cipher ESF is applied in the Internet of Things to provide security for RFID tags and smart cards. ESF algorithm has a 32round generalized Feistel structure, and its round function employs SPnetwork structure. The block size of ESF is 64bit and the key size is 80bit. We search for the impossible differential feature of ESF using the impossible differential cryptanalysis, and present an impossible differential cryptanalysis on 11round ESF, which is based on the 8round impossible differential. It concludes that the full 32round ESF has enough security immunity against the attack.

Key words: block cipher;lightweight;impossible differential;cryptanalysis;ESF