The LG cryptosystem is a public-key encryption scheme in the rank metric using the recent family of $\lambdav-$Gabidulin codes and introduced in 2019 by Lau and Tan. In this paper, we present a cryptanalysis showing that the security of several parameters of the scheme have been overestimated. We also show the existence of some weak keys allowing an attacker to find in polynomial time an alternative private key.

翻译：LG密码系统是一种基于秩度量的公钥加密方案，采用近期提出的$\lambdav-$Gabidulin码族，由Lau和Tan于2019年提出。本文通过密码分析表明，该方案多个参数的安全性被高估。我们同时证明存在部分弱密钥，使得攻击者能在多项式时间内找到等效私钥。