IACR News item: 05 February 2014
Daniel Kraschewski, Hemanta K. Maji, Manoj Prabhakaran, Amit Sahai
ePrint ReportWe provide a polynomial time algorithm to test whether a 2-party finite secure function evaluation (SFE) functionality (possibly randomized) is complete or not. The main tools in our solution include:
-- A formal linear algebraic notion of {\\em redundancy} in a general 2-party randomized function.
-- A notion of {\\em statistically testable games}. A kind of interactive proof in the information-theoretic setting where {\\em both} parties are computationally unbounded but differ in their knowledge of a secret.
-- An extension of the (weak) {\\em converse of Shannon\'s channel coding theorem}, where an adversary can adaptively choose the channel based on it view.
We show that any function $f$, if complete, can implement any (randomized) circuit $C$ using only $O(|C| + k)$ calls to $f$, where $k$ is the statistical security parameter. In particular, for any two-party functionality $g$, this establishes a universal notion of its quantitative ``cryptographic complexity\'\' independent of the setup and has close connections to circuit complexity.
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