Private information retrieval (PIR) inherently requires public-key cryptography. A recent line of work suggests that this barrier can be avoided in secret-key PIR, where the client first preprocesses an N-bit database and retains only a short secret key. This line of work has yielded communication O(N^\epsilon) for any constant \epsilon ... more >>>

An outstanding open problem asks if there exists a boolean matrix with unbounded sign-rank, but bounded randomised communication complexity. We make progress towards this question by proving lower bounds against real linear sketches (a model weaker than sign-rank): Alice and Bob send few linear measurements to a referee, who makes ... more >>>

Cryptographic combiners take $n$ candidate schemes for some primitive $P$, and realize it securely provided that at least $k$ candidates are secure. Intuitively, we expect that if we plug $n$ independent instances of a $\delta$-weak candidate for $P$ into the combiner, assuming $\delta \ll (n-k)/n$, security should be amplified and ... more >>>