This project aims to propose a declarative language dedicated to cryptanalytic problems in symmetric key cryptography using constraint programming (CP) to simplify the representation of attacks, to improve existing attacks and to build new cryptographic primitives that withstand these attacks. We also want to compare the different tools that can be used to solve these problems: SAT and MILP where the constraints are homogeneous and CP where the heterogeneous constraints can allow a more complex treatment. One of the challenges of this project will be to define global constraints dedicated to the case of symmetric cryptography. Concerning constraint programming, this project will define new dedicated global constraints, will improve the underlying filtering and solution search algorithms and will propose dedicated explanations generated automatically.