Jeroboam

Abstract

We introduce a new fast stream cipher, JEROBOAM, working with a key of 128 or 248 bits. JEROBOAM was designed to work with eight internal 32-bit registers called multiply-with-carry generators (mwc). These register are very easy to implement in software and produce a sequence of excellent statistical quality. Per contra, one mwc is easily cracked by a lattice reduction algorithm. Hence, we are lead to interpose a nonlinear filter between these weak registers and the pseudo-random output.