At the third round of the NIST standardization process, three candidates
remain with a security based on error correcting codes, all are key
exchange mechanisms. We will explore them according to their security
assumptions and properties. Among them, we find an historical scheme
(Classic McEliece), as well as schemes using sparse and quasi-cyclic
matrices (BIKE and HQC). We will examine pros and cons, as well as, for
some of them, aspects of their implementation through possible use cases.