Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.
DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.
Suppose we are given a perfect n + c-to-n bit compression function f and we want to construct a larger m + s-to-s bit compression function H instead. What level of security, in particular collision resistance, can we expect from H if it makes r calls to f? We conjecture that typically collisions can be found in 2((nr+cr-m)/(r+1)) queries. This bound is also relevant for building a m + s-to-s bit compression function based on a blockcipher with k-bit keys and n-bit blocks: simply set c = k, or c = 0 in case of fixed keys.
Subhadeep Banik, Daniel Patrick Collins
Serge Vaudenay, Laurane Chloé Angélina Marco, Abdullah Talayhan