Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2018, Director: Artur Travesa i Grau[en] To analyze the security of block ciphers, several methods are used, including primarily linear and differential cryptanalysis. The goal in this dissertation is to study and understand how these cryptographic attacks work, as well as understanding how they can be used for the practical testing of security in this kind of cryptosystems.