On June 9, 2020, Jiseung Kim (김지승) from KIAS presented a talk on some aspects of cryptography, including his recent work “Adventures in Crypto Dark Matter: Attacks, Fixes, and Analysis of weak PRF” jointly with Jung Hee Cheon, Wonhee Cho, and Jeong Han Kim. The title of his talk was “Hardness and concrete security in cryptography“.