PIC Scheme #1 – Stage 1 E(i 1 ) -> E(r 1 (i 1 – i 3 )) E(i 2 ) -> E(r 2 (i 2 – i 3 )) (i 3, j 3 ) E(i 3 ), E(j 3 ), ZKPOK Let E by a homomorphic semantically secure encryption scheme (e.g., Pallier) Suppose we allow accessing each record at most once PK, SK PK Recovers r 1, r 2 iff hasnt previously accessed i 3 From r 1 and r 2 user can reconstruct a secret S 3
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