About Open Problems -- The Past, Evolving Present, and Future of the Discrete Logarithm -- Isogenies in Theory and Praxis -- Another Look at Security Theorems for 1-Key Nested MACs -- Non-extendable Fq-Quadratic Perfect Nonlinear Maps -- Open Problems for Polynomials over Finite Fields and Applications -- Generating Good Span n Sequences Using Orthogonal Functions in Nonlinear Feedback Shift Registers -- Open Problems on the Crosscorrelation of m-Sequences -- Open Problems on With-Carry Sequence Generators -- Open Problems on Binary Bent Functions -- On Semi-bent functions and Related Plateaued Functions over the Galois field F2n -- True Random Number Generators -- How to Sign Paper Contracts? Conjectures and Evidence Related to Equitable and Efficient Collaborative Task Scheduling -- Theoretical Parallel Computing Models for GPU Computing -- Membrane Computing: Basics and Frontiers -- A Panorama of Post-quantum Cryptography.