Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2018, Director: Artur Travesa i Grau[en] Since 2001, AES symmetric private key criptosystem is being used as one of the standards to encrypt a huge amount of messages. AES is analysed from an algebraic point of view using finite field theory, a less common approach in the available standard literature. To finish, the security of the cryptosystem is assessed.