A 3-subset meet-in-the-middle attack: cryptanalysis of the lightweight block cipher KTANTAN

摘要: In this paper we describe a variant of existing meet-in-the-middle attacks on block ciphers. As an application, propose meetin-the-middle that are applicable to the KTANTAN family ciphers accepting key 80 bits. The due some weaknesses in its bitwise schedule. We report attack time complexity 275.170 encryptions full KTANTAN32 cipher with only 3 plaintext/ciphertext pairs and well as 275.044 KTANTAN48 275.584 KTANTAN64 2 pairs. All these work classical model without any related keys. In differential related-key model, demonstrate 218- 174- round differentials holding probability 1. This shows strong property can translate successful nonrelated-key setting. Having extremely low data requirements, valid even RFID-like environments where very limited amount text material may be available attacker.