Problems, solutions and experience of the first international student's Olympiad in cryptography

A detailed overview of the problems, solutions and experience of the first international student's Olympiad in cryptography, NSUCRYPTO'2014, is given. We start with the rules of participation and the description of rounds. All 15 mathematical problems of the Olympiad and their solutions are considered in detail. The problems are about differential characteristics of S-boxes, S-box masking, relations between cyclic rotation and additions modulo $2$ and $2^n$, special linear subspaces in $\mathbb F_2^n$, the number of solutions of the equation $F(x)+F(x+a)=b$ over the finite field $\mathbb F_{2^n}$ and APN functions. Some unsolved problems in symmetric cryptography are also considered.