42,677 research outputs found
Quantum Lazy Sampling and Game-Playing Proofs for Quantum Indifferentiability
Game-playing proofs constitute a powerful framework for non-quantum
cryptographic security arguments, most notably applied in the context of
indifferentiability. An essential ingredient in such proofs is lazy sampling of
random primitives. We develop a quantum game-playing proof framework by
generalizing two recently developed proof techniques. First, we describe how
Zhandry's compressed quantum oracles~(Crypto'19) can be used to do quantum lazy
sampling of a class of non-uniform function distributions. Second, we observe
how Unruh's one-way-to-hiding lemma~(Eurocrypt'14) can also be applied to
compressed oracles, providing a quantum counterpart to the fundamental lemma of
game-playing. Subsequently, we use our game-playing framework to prove quantum
indifferentiability of the sponge construction, assuming a random internal
function
Flexible Structural Neighborhood—a database of protein structural similarities and alignments
Protein structures are flexible, changing their shapes not only upon substrate binding, but also during evolution as a collective effect of mutations, deletions and insertions. A new generation of protein structure comparison algorithms allows for such flexibility; they go beyond identifying the largest common part between two proteins and find hinge regions and patterns of flexibility in protein families. Here we present a Flexible Structural Neighborhood (FSN), a database of structural neighbors of proteins deposited in PDB as seen by a flexible protein structure alignment program FATCAT, developed previously in our group. The database, searchable by a protein PDB code, provides lists of proteins with statistically significant structural similarity and on lower menu levels provides detailed alignments, interactive superposition of structures and positions of hinges that were identified in the comparison. While superficially similar to other structural protein alignment resources, FSN provides a unique resource to study not only protein structural similarity, but also how protein structures change. FSN is available from a server and by direct links from the PDB database
- …