User:Ak947/Raiden Block Cipher

RAIDEN is a recent light-weight 128-bit block cipher. We report in this paper a critical weakness in its key schedule. Besides it reduces a 128-bit key down to 112-bit security, the weakness allows us to mount two related-key attacks. The best of the two attacks has a complexity of about 265. More precisely, the algorithm can be broken with one unknown plaintext, at most 33 unknown related keys, and about 265 trial encryptions. This is the first successful attack on RAIDEN. We also suggest some changes for the key schedule so that our attacks are no more applicable.