Better Steady than Speedy: Full Break of SPEEDY-7-192

Differential attacks are among the most important families of cryptanalysis against symmetric primitives. Since their introduction in 1990, several improvements to basic technique as well many dedicated primitives have been proposed. Most proposed concern key-recovery part. However, when designing a new primitive, security analysis regarding differential is often limited finding best trails over number rounds with branch and bound techniques, poor heuristic then applied deduce total attack could reach. In this work we analyze SPEEDY family block ciphers show how optimize steps procedure for type attacks. For this, implemented search optimal cipher associated multiple probabilities under some constraints non-trivial techniques obtain data key-sieving. This permitted us fully break SPEEDY-7-192, 7-round variant supposed provide 192-bit security. Our demonstrates others need better understand subtleties order get meaningful estimates on offered by these