In this paper we present an attack on a recently proposed code-based Private Information Retrieval (PIR) scheme. Indeed, the server can retrieve the index of the desired file with high probability in polynomial time. The attack relies on the fact that random codes over finite rings are free with high probability and that the dimension of the rowspan of the query matrix decreases when the rows corresponding to the desired index are removed.

翻译：本文针对一种近期提出的基于编码的隐私信息检索(PIR)方案提出了一种攻击方法。服务器能够在多项式时间内以高概率检索到目标文件的索引。该攻击利用了以下事实：有限环上的随机编码以高概率为自由模，且当移除与目标索引对应的行时，查询矩阵的行空间的维数会降低。