Cryptanalysis of a PIR Scheme based on Linear Codes over Rings
This work identifies a security flaw in a specific PIR scheme, which is incremental as it critiques an existing method rather than introducing a new one.
The authors attacked a recently proposed code-based Private Information Retrieval (PIR) scheme, showing that the server can retrieve the desired file index with high probability in polynomial time.
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.