PIR: query vector compression and expansion

[gpestana]

Query vector compression and expansion for PIR

At a high level, our goal is to realize the following picture: the client sends one ciphertext containing an encryption of its desired index i to the server, and the server inexpensively evaluates a function EXPAND that outputs n ciphertexts containing an encryption of 0 or 1 (where the i th ciphertext encrypts 1 and others encrypt 0). The server can then use these n ciphertexts as a query and execute the protocol as before. [1]

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[1] PIR with Compressed Queries and Amortized Query Processing (https://ieeexplore.ieee.org/document/8418648)

[gpestana]

Fan-Vercauteren FHE cryptosystem: [2] Somewhat Practical Fully Homomorphic Encryption (https://eprint.iacr.org/2012/144.pdf)