Our research has focused on the study of complex dynamics and on their use in both information security and bioinformatics. Our first work has been on chaotic discrete dynamical systems, and links have been established between these dynamics on the one hand, and either random or complex behaviors. Applications on information security are on the pseudorandom numbers generation, hash functions, information hiding, and on security aspects on wireless sensor networks. On the bioinformatics level, we have applied our studies of complex systems to the evolution of genomes and to protein folding.