On the Capacity of Weakly-Private Information Retrieval
Zhuqing Jia · eScholarship (California Digital Library) · 2019
The problem of weakly-private information retrieval, is a variant of private informationretrieval, where the user wants to retrieve 1 out of K messages from a distributed storagesystem with N servers that stores all K messages, and is willing to leak some informationof the identity of the desired message. In this work, we study the problem of weakly-privateinformation retrieval. A novel information leakage metric is proposed, and the capacity forthe setting of N = 2 servers, and arbitrary number of messages K is characterized. Inparticular, in the capacity achieving scheme, designing the distribution of the non-uniformlydistributed noise Z turns out to be the key to achieve the capacity.