Code-based cryptography

As the threat of building quantum computers which would break most of the used ciphers increases, so does the interest in an alternative solution. In the first part of this thesis, we consider Goppa codes which are error-correcting codes used in some post-quantum cryptosystems. We show that they have a large minimum distance and describe an efficient decoding algorithm. Furthermore, we consider McEliece public-key cryptosystem based on Goppa codes and we give a short analysis of its security which remains high even after forty years of analysis