SIAM Journal on Computing

For an undirected edge-weighted graph $G$ and a set $R$ of pairs of vertices called pairs of terminals, a multicut is a set of edges such that removing these edges from $G$ disconnects each pair in $R$. We provide an algorithm computing a $(1+\varepsilon)$-...

In the conditional disclosure of secrets (CDS) problem [Gertner et al., J. Comput. System Sci., 60 (2000), pp. 592--629] Alice and Bob, who hold inputs $x$ and $y$, respectively, wish to release a common secret $s$ to Carol (who knows both $x$ and $y$) if ...

We show that any multiparty functionality can be evaluated using a 2-round protocol with perfect correctness and perfect semihonest security, provided that the majority of parties are honest. This settles the round complexity of information-theoretic ...

Much of modern cryptography, starting from public-key encryption and going beyond, is based on the hardness of structured (mostly algebraic) problems like factoring, discrete log, or finding short lattice vectors. While structure is perhaps what enables ...

Let $P$łabelpage1 be a set of $n$ points in the plane. We consider a variation of the classical Erdös--Szekeres problem, presenting efficient algorithms with $O(n^3)$ running time and $O(n^2)$ space complexity that compute (1) a subset $S$ of $P$ such that ...

Lifting theorems are theorems that relate the query complexity of a function $f:\{0,1\}^{n}\to \{0,1\}$ to the communication complexity of the composed function $f\circ g^{n}$ for some “gadget” $g:\{ 0,1\}^{b}\times \{0,1\}^{b}\to \{0,1\}$. Such theorems ...

We initiate the study of computing (near-)optimal contracts in succinctly representable principal-agent settings. Here optimality means maximizing the principal's expected payoff over all incentive-compatible contracts---known in economics as “second-best” ...