  The security of code-based cryptography usually relies on the hardness of the
syndrome decoding (SD) problem for the Hamming weight. The best generic
algorithms are all improvements of an old algorithm by Prange, and they are
known under the name of Information Set Decoding (ISD) algorithms. This work
aims to extend ISD algorithms' scope by changing the underlying weight function
and alphabet size of SD. More precisely, we show how to use Wagner's algorithm
in the ISD framework to solve SD for a wide range of weight functions. We also
calculate the asymptotic complexities of ISD algorithms both in the classical
and quantum case. We then apply our results to the Lee metric, which currently
receives a significant amount of attention. By providing the parameters of SD
for which decoding in the Lee weight seems to be the hardest, our study could
have several applications for designing code-based cryptosystems and their
security analysis, especially against quantum adversaries.
