Message authentication is one of the basic tasks in cryptography. Even though message authentication codes are around for decades, for many of them their exact security is not known. In the talk you will see two examples of algorithms where it was worth re-visiting their proofs of security. New proofs for these constructions will be explained, as well as new matching attacks. Together, they expose the true security of both constructions.
Michal Rybár is a Ph.D. candidate in the Pietrzak group, working on message authentication codes and symmetric cryptography. He obtained his Master's degree from the University of Bristol in the United Kingdom, before he joined IST in 2012.