Several recently proposed code-based cryptosystems base their security on a slightly generalized version of the classical (syndrome) decoding problem. Namely, in the so-called restricted (syndrome) decoding problem, the error values stem from a restricted set. In this paper, we propose new generic decoders, that are inspired by subset sum solvers and tailored to the new setting. The introduced algorithms take the restricted structure of the error set into account in order to utilize the representation technique efficiently. This leads to a considerable decrease in the security levels of recently published code-based cryptosystems.

翻译：最近提出的几种基于编码的密码系统，其安全性建立在经典（伴随式）解码问题的一个略微广义化的版本之上。具体而言，在所谓的受限（伴随式）解码问题中，错误值来源于一个受限集合。本文提出了一类新型通用解码器，其灵感来源于子集和求解器，并针对这一新场景进行了定制。所引入的算法充分考虑了错误集的受限结构，从而高效地利用了表示技术。这显著降低了近期发表的基于编码的密码系统的安全级别。