A tight lower bound for restricted pir protocols
We show that any 1-round 2-server Private Information Retrieval Protocol where the answers are one bit long must ask questions that are at least n−2 bits long, which is nearly equal to the known n−1 upper bound. This improves upon the approximately 0.25n lower bound of Kerenidis and deWolf while avoiding their use of quantum techniques.
Keywords.Private information retrieval lower bounds privacy
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