Improved Differential Fault Attack on the Block Cipher SPECK

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.