This lecture delves into the (in)security of ROS, focusing on the k-sum problem and Wagner's k-list algorithm. It explores the implications of ROS Attack for IA, blind signatures, and Schnorr's Blind Signature. The instructors Max Duparc and Christophe Marciot present a detailed analysis of ROS security, including the use of random inhomogeneities in overdetermined solvable linear systems.