Improved Differential Fault Attack on the Block Cipher SPECK

Abstract

SPECK is a family of lightweight block cipherspublished by the U.S. National Security Agency in 2013. TheSPECK family consists of 10 versions, supporting a wide rangeof block and key sizes. Recently H. Tupsamudre et al. gave anapproach to recovering the last round key of SPECK familywith n/3 fault injections, where 2n is the block size. In thispaper, we present two improved differential fault attacks on theSPECK family under different fault models. The first attackassumes a more practical random fault model and recovers thelast round key with about 5 ~ 8 fault injections on all versionswith different block sizes, which is far less than that of H. Tupsamudre et al.'s attack. The second attack only requires 4specific faults to recover the last round key (except the mostsignificant bit) over an arbitrary block size under a chosen-valuefault model.