pinecone/core-2020-05-10-deduplication huggingface dataset:
3-Message Zero Knowledge Against Human Ignorance

The notion of Zero Knowledge has driven the field of cryptography since its conception over thirty years ago. It is well established that two-message zero-knowledge protocols for NP do not exist, and that four-message zero-knowledge arguments exist under the minimal assumption of one-way functions. Resolving the precise round complexity of zero-knowledge has been an outstanding open problem for far too long.

In this work, we present a three-message zero-knowledge argument system with soundness against uniform polynomial-time cheating provers. The main component in our construction is the recent delegation protocol for RAM computations (Kalai and Paneth, TCC 2016B and Brakerski, Holmgren and Kalai, ePrint 2016). Concretely, we rely on a three-message variant of their protocol based on a key-less collision-resistant hash functions secure against uniform adversaries as well as other standard primitives.

More generally, beyond uniform provers, our protocol provides a natural and meaningful security guarantee against real-world adversaries, which we formalize following Rogaway’s “human-ignorance” approach (VIETCRYPT 2006): in a nutshell, we give an explicit uniform reduction from any adversary breaking the soundness of our protocol to finding collisions in the underlying hash function.National Science Foundation (U.S.) (Award CNS-1350619)National Science Foundation (U.S.) (Award CNS-1413964
Multi-Key homomorphic authenticators

Homomorphic authenticators (HAs) enable a client to authenticate a large collection of data elements m1,...,mt and outsource them, along with the corresponding authenticators, to an untrusted server. At any later point, the server can generate a short authenticator ?f,y vouching for the correctness of the output y of a function f computed on the outsourced data, i.e., y=f(m1,...,mt). Recently researchers have focused on HAs as a solution, with minimal communication and interaction, to the problem of delegating computation on outsourced data. The notion of HAs studied so far, however, only supports executions (and proofs of correctness) of computations over data authenticated by a single user. Motivated by realistic scenarios (ubiquitous computing, sensor networks, etc.) in which large datasets include data provided by multiple users, we study the concept of multi?key homomorphic authenticators. In a nutshell, multi-key HAs are like HAs with the extra feature of allowing the holder of public evaluation keys to compute on data authenticated under different secret keys. In this paper, we introduce and formally define multi-key HAs. Secondly, we propose a construction of a multi-key homomorphic signature based on standard lattices and supporting the evaluation of circuits of bounded polynomial depth. Thirdly, we provide a construction of multi-key homomorphic MACs based only on pseudorandom functions and supporting the evaluation of low-degree arithmetic circuits. Albeit being less expressive and only secretly verifiable, the latter construction presents interesting efficiency properties
Zero-Knowledge Arguments for Matrix-Vector Relations and Lattice-Based Group Encryption

International audienceGroup encryption (GE) is the natural encryption analogue of group signatures in that it allows verifiably encrypting messages for some anonymous member of a group while providing evidence that the receiver is a properly certified group member. Should the need arise, an opening authority is capable of identifying the receiver of any ciphertext. As introduced by Kiayias, Tsiounis and Yung (Asiacrypt'07), GE is motivated by applications in the context of oblivious retriever storage systems, anonymous third parties and hierarchical group signatures. This paper provides the first realization of group encryption under lattice assumptions. Our construction is proved secure in the standard model (assuming interaction in the proving phase) under the Learning-With-Errors (LWE) and Short-Integer-Solution (SIS) assumptions. As a crucial component of our system, we describe a new zero-knowledge argument system allowing to demonstrate that a given ciphertext is a valid encryption under some hidden but certified public key, which incurs to prove quadratic statements about LWE relations. Specifically, our protocol allows arguing knowledge of witnesses consisting of X ∈ Z m×n q , s ∈ Z n q and a small-norm e ∈ Z m which underlie a public vector b = X · s + e ∈ Z m q while simultaneously proving that the matrix X ∈ Z m×n q has been correctly certified. We believe our proof system to be useful in other applications involving zero-knowledge proofs in the lattice setting
Computer-aided verification in mechanism design

In mechanism design, the gold standard solution concepts are dominant
strategy incentive compatibility and Bayesian incentive compatibility. These
solution concepts relieve the (possibly unsophisticated) bidders from the need
to engage in complicated strategizing. While incentive properties are simple to
state, their proofs are specific to the mechanism and can be quite complex.
This raises two concerns. From a practical perspective, checking a complex
proof can be a tedious process, often requiring experts knowledgeable in
mechanism design. Furthermore, from a modeling perspective, if unsophisticated
agents are unconvinced of incentive properties, they may strategize in
unpredictable ways.
  To address both concerns, we explore techniques from computer-aided
verification to construct formal proofs of incentive properties. Because formal
proofs can be automatically checked, agents do not need to manually check the
properties, or even understand the proof. To demonstrate, we present the
verification of a sophisticated mechanism: the generic reduction from Bayesian
incentive compatible mechanism design to algorithm design given by Hartline,
Kleinberg, and Malekian. This mechanism presents new challenges for formal
verification, including essential use of randomness from both the execution of
the mechanism and from the prior type distributions. As an immediate
consequence, our work also formalizes Bayesian incentive compatibility for the
entire family of mechanisms derived via this reduction. Finally, as an
intermediate step in our formalization, we provide the first formal
verification of incentive compatibility for the celebrated
Vickrey-Clarke-Groves mechanism
Observed communication semantics for classical processes

Classical Linear Logic (CLL) has long inspired readings of its proofs as communicating processes. Wadler's CP calculus is one of these readings. Wadler gave CP an operational semantics by selecting a subset of the cut-elimination rules of CLL to use as reduction rules. This semantics has an appealing close connection to the logic, but does not resolve the status of the other cut-elimination rules, and does not admit an obvious notion of observational equivalence. We propose a new operational semantics for CP based on the idea of observing communication, and use this semantics to define an intuitively reasonable notion of observational equivalence. To reason about observational equivalence, we use the standard relational denotational semantics of CLL. We show that this denotational semantics is adequate for our operational semantics. This allows us to deduce that, for instance, all the cut-elimination rules of CLL are observational equivalences
Automated verification of dynamic root of trust protocols (long version)

Automated verification of security protocols based on dynamic root of trust,
typically relying on protected hardware such as TPM, involves several
challenges that we address in this paper. We model the semantics of trusted
computing platforms (including CPU, TPM, OS, and other essential components)
and of associated protocols in a classical process calculus accepted by
ProVerif. As part of the formalization effort, we introduce new equational
theories for representing TPM specific platform states and dynamically loaded
programs. Formal models for such an extensive set of features cannot be readily
handled by ProVerif, due especially to the search space generated by unbounded
extensions of TPM registers. In this context we introduce a transformation of
the TPM process, that simplifies the structure of the search space for
automated verification, while preserving the security properties of interest.
This allows to run ProVerif on our proposed models, so we can derive
automatically security guarantees for protocols running in a dynamic root of
trust context.Comment: 27 pages with Appendi
Security analysis of cache replacement policies

Modern computer architectures share physical resources between different programs in order to increase area-, energy-, and cost- efficiency. Unfortunately, sharing often gives rise to side channels that can be exploited for extracting or transmitting sensitive information. We currently lack techniques for systematic reasoning about this interplay between security and efficiency. In particular, there is no established way for quantifying security properties of shared caches. In this paper, we propose a novel model that enables us to characterize important security properties of caches. Our model encompasses two aspects: (1) The amount of information that can be absorbed by a cache, and (2) the amount of information that can effectively be extracted from the cache by an adversary. We use our model to compute both quantities for common cache replacement policies (FIFO, LRU, and PLRU) and to compare their isolation properties. We further show how our model for information extraction leads to an algorithm that can be used to improve the bounds delivered by the CacheAudit static analyzer
Coherence Spaces and Uniform Continuity

In this paper, we consider a model of classical linear logic based on
coherence spaces endowed with a notion of totality. If we restrict ourselves to
total objects, each coherence space can be regarded as a uniform space and each
linear map as a uniformly continuous function. The linear exponential comonad
then assigns to each uniform space X the finest uniform space !X compatible
with X. By a standard realizability construction, it is possible to consider a
theory of representations in our model. Each (separable, metrizable) uniform
space, such as the real line, can then be represented by (a partial surjecive
map from) a coherence space with totality. The following holds under certain
mild conditions: a function between uniform spaces X and Y is uniformly
continuous if and only if it is realized by a total linear map between the
coherence spaces representing X and Y
The Paths to Choreography Extraction

Choreographies are global descriptions of interactions among concurrent
components, most notably used in the settings of verification (e.g., Multiparty
Session Types) and synthesis of correct-by-construction software (Choreographic
Programming). They require a top-down approach: programmers first write
choreographies, and then use them to verify or synthesize their programs.
However, most existing software does not come with choreographies yet, which
prevents their application.
  To attack this problem, we propose a novel methodology (called choreography
extraction) that, given a set of programs or protocol specifications,
automatically constructs a choreography that describes their behavior. The key
to our extraction is identifying a set of paths in a graph that represents the
symbolic execution of the programs of interest. Our method improves on previous
work in several directions: we can now deal with programs that are equipped
with a state and internal computation capabilities; time complexity is
dramatically better; we capture programs that are correct but not necessarily
synchronizable, i.e., they work because they exploit asynchronous
communication
Partiality, Revisited: The Partiality Monad as a Quotient
  Inductive-Inductive Type

Capretta's delay monad can be used to model partial computations, but it has
the "wrong" notion of built-in equality, strong bisimilarity. An alternative is
to quotient the delay monad by the "right" notion of equality, weak
bisimilarity. However, recent work by Chapman et al. suggests that it is
impossible to define a monad structure on the resulting construction in common
forms of type theory without assuming (instances of) the axiom of countable
choice. Using an idea from homotopy type theory - a higher inductive-inductive
type - we construct a partiality monad without relying on countable choice. We
prove that, in the presence of countable choice, our partiality monad is
equivalent to the delay monad quotiented by weak bisimilarity. Furthermore we
outline several applications.Comment: v1: 16 pages. v2: 17 pages, llncs style. Minor changes. The final
  publication is available at Springer via
  http://dx.doi.org/10.1007/978-3-662-54458-7_3
On the Semantics of Intensionality

In this paper we propose a categorical theory of intensionality. We first
revisit the notion of intensionality, and discuss we its relevance to logic and
computer science. It turns out that 1-category theory is not the most
appropriate vehicle for studying the interplay of extension and intension. We
are thus led to consider the P-categories of \v{C}ubri\'{c}, Dybjer and Scott,
which are categories only up to a partial equivalence relation (PER). In this
setting, we introduce a new P-categorical construct, that of exposures.
Exposures are very nearly functors, except that they do not preserve the PERs
of the P-category. Inspired by the categorical semantics of modal logic, we
begin to develop their theory. Our leading examples demonstrate that an
exposure is an abstraction of well-behaved intensional devices, such as G\"odel
numberings. The outcome is a unifying framework in which classic results of
Kleene, G\"odel, Tarski and Rice find concise, clear formulations, and where
each logical device or assumption involved in their proofs can be expressed in
the same algebraic manner
Explicit connection actions in multiparty session types

This work extends asynchronous multiparty session types (MPST) with explicit connection actions to support protocols with op- tional and dynamic participants. The actions by which endpoints are connected and disconnected are a key element of real-world protocols that is not treated in existing MPST works. In addition, the use cases motivating explicit connections often require a more relaxed form of mul- tiparty choice: these extensions do not satisfy the conservative restric- tions used to ensure safety in standard syntactic MPST. Instead, we de- velop a modelling-based approach to validate MPST safety and progress for these enriched protocols. We present a toolchain implementation, for distributed programming based on our extended MPST in Java, and a core formalism, demonstrating the soundness of our approach. We discuss key implementation issues related to the proposed extensions: a practi- cal treatment of choice subtyping for MPST progress, and multiparty correlation of dynamic binary connections
From LTL and Limit-Deterministic B\"uchi Automata to Deterministic
  Parity Automata

Controller synthesis for general linear temporal logic (LTL) objectives is a
challenging task. The standard approach involves translating the LTL objective
into a deterministic parity automaton (DPA) by means of the Safra-Piterman
construction. One of the challenges is the size of the DPA, which often grows
very fast in practice, and can reach double exponential size in the length of
the LTL formula. In this paper we describe a single exponential translation
from limit-deterministic B\"uchi automata (LDBA) to DPA, and show that it can
be concatenated with a recent efficient translation from LTL to LDBA to yield a
double exponential, \enquote{Safraless} LTL-to-DPA construction. We also report
on an implementation, a comparison with the SPOT library, and performance on
several sets of formulas, including instances from the 2016 SyntComp
competition
Minimization of Visibly Pushdown Automata Using Partial Max-SAT

We consider the problem of state-space reduction for nondeterministic
weakly-hierarchical visibly pushdown automata (VPA). VPA recognize a robust and
algorithmically tractable fragment of context-free languages that is natural
for modeling programs.
  We define an equivalence relation that is sufficient for language-preserving
quotienting of VPA. Our definition allows to merge states that have different
behavior, as long as they show the same behavior for reachable equivalent
stacks. We encode the existence of such a relation as a Boolean partial maximum
satisfiability (PMax-SAT) problem and present an algorithm that quickly finds
satisfying assignments. These assignments are sub-optimal solutions to the
PMax-SAT problem but can still lead to a significant reduction of states.
  We integrated our method in the automata-based software verifier Ultimate
Automizer and show performance improvements on benchmarks from the software
verification competition SV-COMP.Comment: extended versio
Efficient Certified Resolution Proof Checking

We present a novel propositional proof tracing format that eliminates complex
processing, thus enabling efficient (formal) proof checking. The benefits of
this format are demonstrated by implementing a proof checker in C, which
outperforms a state-of-the-art checker by two orders of magnitude. We then
formalize the theory underlying propositional proof checking in Coq, and
extract a correct-by-construction proof checker for our format from the
formalization. An empirical evaluation using 280 unsatisfiable instances from
the 2015 and 2016 SAT competitions shows that this certified checker usually
performs comparably to a state-of-the-art non-certified proof checker. Using
this format, we formally verify the recent 200 TB proof of the Boolean
Pythagorean Triples conjecture
VD-PSI : verifiable delegated private set intersection on outsourced private datasets

Private set intersection (PSI) protocols have many real world applications. With the emergence of cloud computing the need arises for PSI protocols on outsourced datasets where the computation is delegated to the cloud. However, due to the possibility of cloud misbehaviors, it is essential to verify the correctness of any delegated computation, and the integrity of any outsourced datasets. Verifiable Computation on private datasets that does not leak any information about the data is very challenging, especially when the datasets are outsourced independently by different clients. In this paper we present VD-PSI, a protocol that allows multiple clients to outsource their private datasets and delegate computation of set intersection to the cloud, while being able to verify the correctness of the result. Clients can independently prepare and upload their datasets, and with their agreement can verifiably delegate the computation of set intersection an unlimited number of times, without the need to download or maintain a local copy of their data. The protocol ensures that the cloud learns nothing about the datasets and the intersection. VD-PSI is efficient as its verification cost is linear to the intersection cardinality, and its computation and communication costs are linear to the dataset cardinality. Also, we provide a formal security analysis in the standard model
Categories: How I Learned to Stop Worrying and Love Two Sorts

RS-frames were introduced by Gehrke as relational semantics for substructural
logics. They are two-sorted structures, based on RS-polarities with additional
relations used to interpret modalities. We propose an intuitive, epistemic
interpretation of RS-frames for modal logic, in terms of categorization systems
and agents' subjective interpretations of these systems. Categorization systems
are a key to any decision-making process and are widely studied in the social
and management sciences.
  A set of objects together with a set of properties and an incidence relation
connecting objects with their properties forms a polarity which can be `pruned'
into an RS-polarity. Potential categories emerge as the Galois-stable sets of
this polarity, just like the concepts of Formal Concept Analysis. An agent's
beliefs about objects and their properties (which might be partial) is modelled
by a relation which gives rise to a normal modal operator expressing the
agent's beliefs about category membership. Fixed-points of the iterations of
the belief modalities of all agents are used to model categories constructed
through social interaction.Comment: References update
On the Length of Medial-Switch-Mix Derivations

Switch and medial are two inference rules that play a central role in many deep inference proof systems. In specific proof systems, the mix rule may also be present. In this paper we show that the maximal length of a derivation using only the inference rules for switch, medial, and mix, modulo associativity and commutativity of the two binary connectives involved, is quadratic in the size of the formula at the conclusion of the derivation. This shows, at the same time, the termination of the rewrite system
Motion Artifact Detection in Confocal Laser Endomicroscopy Images

Confocal Laser Endomicroscopy (CLE), an optical imaging technique allowing
non-invasive examination of the mucosa on a (sub)cellular level, has proven to
be a valuable diagnostic tool in gastroenterology and shows promising results
in various anatomical regions including the oral cavity. Recently, the
feasibility of automatic carcinoma detection for CLE images of sufficient
quality was shown. However, in real world data sets a high amount of CLE images
is corrupted by artifacts. Amongst the most prevalent artifact types are
motion-induced image deteriorations. In the scope of this work, algorithmic
approaches for the automatic detection of motion artifact-tainted image regions
were developed. Hence, this work provides an important step towards clinical
applicability of automatic carcinoma detection. Both, conventional machine
learning and novel, deep learning-based approaches were assessed. The deep
learning-based approach outperforms the conventional approaches, attaining an
AUC of 0.90
Configuration Spaces of Equal Spheres Touching a Given Sphere: The
  Twelve Spheres Problem

The problem of twelve spheres is to understand, as a function of $r \in
(0,r_{max}(12)]$, the configuration space of $12$ non-overlapping equal spheres
of radius $r$ touching a central unit sphere. It considers to what extent, and
in what fashion, touching spheres can be varied, subject to the constraint of
always touching the central sphere. Such constrained motion problems are of
interest in physics and materials science, and the problem involves topology
and geometry. This paper reviews the history of work on this problem, presents
some new results, and formulates some conjectures. It also presents general
results on configuration spaces of $N$ spheres of radius $r$ touching a central
unit sphere, with emphasis on $3 \le N \le 14$. The problem of determining the
maximal radius $r_{max}(N)$ is a version of the Tammes problem, to which
L\'aszl\'o Fejes T\'oth made significant contributions.Comment: (v3) 53 pages, 12 figures. In celebration of L\'aszl\'o Fejes T\'oth.
  (FT100). Minor updates to language in the introduction. Title modified to
  include an initial clause. Abstract language modifie
Combinatorial distance geometry in normed spaces

We survey problems and results from combinatorial geometry in normed spaces,
concentrating on problems that involve distances. These include various
properties of unit-distance graphs, minimum-distance graphs, diameter graphs,
as well as minimum spanning trees and Steiner minimum trees. In particular, we
discuss translative kissing (or Hadwiger) numbers, equilateral sets, and the
Borsuk problem in normed spaces. We show how to use the angular measure of
Peter Brass to prove various statements about Hadwiger and blocking numbers of
convex bodies in the plane, including some new results. We also include some
new results on thin cones and their application to distinct distances and other
combinatorial problems for normed spaces.Comment: 43 pages, 4 figures, New Trends in Intuitive Geometry, Springer, to
  appea