On the morning that the CAESAR competition entered its third round , track A of CRYPTO 2016 begin with a session on provable security for symmetric cryptography. It contained 5 talks, all of which were very well presented. In each case the results were given in context, along with a sketch of the key techniques behind their proofs, and very clear diagrams. First up was Viet Tung Hoang, presenting joint work with Stefano Tessaro on the multi-user security of Key-alternating Ciphers. Key Alternati