70,633 research outputs found
An SVP attack on Vortex
In [BS22], the authors proposed a lattice based hash function that is useful for building zero-knowledge proofs with superior performance. In this short note we analysis the underlying lattice problem with the classic shortest vector problem, and show that 2 out of 15 proposed parameter sets for this hash function do not achieve the claimed security
Bulletproofs With Stochastic Equation Sets
Bulletproofs are general-purpose Zero Knowledge Proof protocols that allow a Prover to demonstrate to a Verifier knowledge of a solution to a set of equations, represented as a Rank 1 Constraint System.
We present a protocol extending the standard Bulletproof protocol, which introduces a second layer of interactivity to the protocol, by allowing the Verifier to choose the set of equations after the Prover has already committed to portions of the solution.
We show that such Verifier-chosen (or stochastically-chosen) equation sets can be used to design smaller equation sets with less variables that have the same proving-power as their larger, deterministic counterparts but are, in practice, orders of magnitude faster both in proof generation and in proof verification, and even reduce the size of the resulting proofs. We demonstrate this with an example from a real-world application.
Our method maintains all the classical benefits of the Bulletproof approach: efficient proof generation, efficient proof checking, extremely short proofs, and the ability to use Fiat-Shamir challenges in order to turn an interactive proof into a non-interactive proof
Notes for Miscellaneous Lectures
Here I share a few notes I used in various course lectures, talks, etc. Some
may be just calculations that in the textbooks are more complicated, scattered,
or less specific; others may be simple observations I found useful or curious.Comment: 6 pages. New section 6 adde
A Practical Set-Membership Proof for Privacy-Preserving NFC Mobile Ticketing
To ensure the privacy of users in transport systems, researchers are working
on new protocols providing the best security guarantees while respecting
functional requirements of transport operators. In this paper, we design a
secure NFC m-ticketing protocol for public transport that preserves users'
anonymity and prevents transport operators from tracing their customers' trips.
To this end, we introduce a new practical set-membership proof that does not
require provers nor verifiers (but in a specific scenario for verifiers) to
perform pairing computations. It is therefore particularly suitable for our
(ticketing) setting where provers hold SIM/UICC cards that do not support such
costly computations. We also propose several optimizations of Boneh-Boyen type
signature schemes, which are of independent interest, increasing their
performance and efficiency during NFC transactions. Our m-ticketing protocol
offers greater flexibility compared to previous solutions as it enables the
post-payment and the off-line validation of m-tickets. By implementing a
prototype using a standard NFC SIM card, we show that it fulfils the stringent
functional requirement imposed by transport operators whilst using strong
security parameters. In particular, a validation can be completed in 184.25 ms
when the mobile is switched on, and in 266.52 ms when the mobile is switched
off or its battery is flat
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