Differential attack on five rounds of the SC2000 block cipher

SC2000 is a 128-bit block cipher with a user key of 128, 192 or 256 bits, which employs a total of 6.5 rounds if a 128-bit user key is used. It is a CRYPTREC recommended e-government cipher. In this paper we describe one 4.75-round differential characteristic with probability $2^{126}$ of SC2000 and thirty 4.75-round differential characteristics with probability $2^{¿127}$. Finally, we exploit these 4.75-round differentials to conduct a differential cryptanalysis attack on a 5-round reduced version of SC2000 when used with a 128-bit key. The attack suggests for the first time that the safety margin of SC2000 with a 128-bit key decreases below one and a half rounds

A Salad of Block Ciphers

This book is a survey on the state of the art in block cipher design and analysis. It is work in progress, and it has been for the good part of the last three years -- sadly, for various reasons no significant change has been made during the last twelve months. However, it is also in a self-contained, useable, and relatively polished state, and for this reason I have decided to release this \textit{snapshot} onto the public as a service to the cryptographic community, both in order to obtain feedback, and also as a means to give something back to the community from which I have learned much. At some point I will produce a final version -- whatever being a ``final version\u27\u27 means in the constantly evolving field of block cipher design -- and I will publish it. In the meantime I hope the material contained here will be useful to other people