Cryptanalysis of Reduced-Round KLEIN Block Cipher

摘要

KLEIN is a lightweight block cipher proposed in RFIDSec 2011 which combines 4-bit S-box with Rijndael's byte-oriented MixColumn. In this paper, we first investigate the security of KLEIN against truncated differential analysis. We construct a 6-round truncated differential distinguisher based on a careful observation about the characteristic of KLEIN round function. With the help of this new distinguisher, we give a truncated differential analysis of 8-round KLEIN-64 with the data complexity of 2~(32) and time complexity of 2~(46.8) encryptions. Furthermore, we study the security of KLEIN against integral analysis and present an integral analysis of 7-round KLEIN-64 and 8-round KLEIN-80 using a 5-round distinguisher, which is constructed by utilizing higher-order integral and higher-order differential properties.