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Electronic Colloquium on Computational Complexity

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Reports tagged with worst-case to average-case reductions:
TR05-158 | 12th December 2005
Chris Peikert, Alon Rosen

Efficient Collision-Resistant Hashing from Worst-Case Assumptions on Cyclic Lattices

The generalized knapsack function is defined as $f_{\a}(\x) = \sum_i
a_i \cdot x_i$, where $\a = (a_1, \ldots, a_m)$ consists of $m$
elements from some ring $R$, and $\x = (x_1, \ldots, x_m)$ consists
of $m$ coefficients from a specified subset $S \subseteq R$.
Micciancio ... more >>>

TR06-147 | 27th November 2006
Chris Peikert, Alon Rosen

Lattices that Admit Logarithmic Worst-Case to Average-Case Connection Factors

Revisions: 1

We demonstrate an \emph{average-case} problem which is as hard as
finding $\gamma(n)$-approximate shortest vectors in certain
$n$-dimensional lattices in the \emph{worst case}, where $\gamma(n)
= O(\sqrt{\log n})$. The previously best known factor for any class
of lattices was $\gamma(n) = \tilde{O}(n)$.

To obtain our ... more >>>

TR06-148 | 4th December 2006
Chris Peikert

Limits on the Hardness of Lattice Problems in $\ell_p$ Norms

Revisions: 1

We show that for any $p \geq 2$, lattice problems in the $\ell_p$
norm are subject to all the same limits on hardness as are known
for the $\ell_2$ norm. In particular, for lattices of dimension

* Approximating the shortest and closest vector in ... more >>>

TR12-156 | 12th November 2012
Andrej Bogdanov, Chin Ho Lee

Limits of provable security for homomorphic encryption

Revisions: 1

We show that public-key bit encryption schemes which support weak homomorphic evaluation of parity or majority cannot be proved message indistinguishable beyond AM intersect coAM via general (adaptive) reductions, and beyond statistical zero-knowledge via reductions of constant query complexity.

Previous works on the limitation of reductions for proving security of ... more >>>

TR17-130 | 30th August 2017
Oded Goldreich, Guy Rothblum

Worst-case to Average-case reductions for subclasses of P

Revisions: 4

For every polynomial $q$, we present worst-case to average-case (almost-linear-time) reductions for a class of problems in $\cal P$ that are widely conjectured not to be solvable in time $q$.
These classes contain, for example, the problems of counting the number of $k$-cliques in a graph, for any fixed $k\geq3$.
more >>>

TR18-046 | 9th March 2018
Oded Goldreich, Guy Rothblum

Counting $t$-cliques: Worst-case to average-case reductions and Direct interactive proof systems

Revisions: 2

We present two main results regarding the complexity of counting the number of $t$-cliques in a graph.

\item{\em A worst-case to average-case reduction}:
We reduce counting $t$-cliques in any $n$-vertex graph to counting $t$-cliques in typical $n$-vertex graphs that are drawn from a simple distribution of min-entropy ${\widetilde\Omega}(n^2)$. For ... more >>>

TR20-104 | 12th July 2020
Oded Goldreich

On Counting $t$-Cliques Mod 2

Revisions: 3

For a constant integer $t$, we consider the problem of counting the number of $t$-cliques $\bmod 2$ in a given graph.
We show that this problem is not easier than determining whether a given graph contains a $t$-clique, and present a simple worst-case to average-case reduction for it. The ... more >>>

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