Summing up Smart Transitions

Neta Elad, Sophie Rain*, Neil Immerman, Laura Kovács, Mooly Sagiv

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Scopus citations

Abstract

Some of the most significant high-level properties of currencies are the sums of certain account balances. Properties of such sums can ensure the integrity of currencies and transactions. For example, the sum of balances should not be changed by a transfer operation. Currencies manipulated by code present a verification challenge to mathematically prove their integrity by reasoning about computer programs that operate over them, e.g., in Solidity. The ability to reason about sums is essential: even the simplest ERC-20 token standard of the Ethereum community provides a way to access the total supply of balances. Unfortunately, reasoning about code written against this interface is non-trivial: the number of addresses is unbounded, and establishing global invariants like the preservation of the sum of the balances by operations like transfer requires higher-order reasoning. In particular, automated reasoners do not provide ways to specify summations of arbitrary length. In this paper, we present a generalization of first-order logic which can express the unbounded sum of balances. We prove the decidablity of one of our extensions and the undecidability of a slightly richer one. We introduce first-order encodings to automate reasoning over software transitions with summations. We demonstrate the applicability of our results by using SMT solvers and first-order provers for validating the correctness of common transitions in smart contracts.

Original languageEnglish
Title of host publicationComputer Aided Verification - 33rd International Conference, CAV 2021, Proceedings
EditorsAlexandra Silva, K. Rustan Leino
PublisherSpringer Science and Business Media Deutschland GmbH
Pages317-340
Number of pages24
ISBN (Print)9783030816841
DOIs
StatePublished - 2021
Event33rd International Conference on Computer Aided Verification, CAV 2021 - Virtual, Online
Duration: 20 Jul 202123 Jul 2021

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12759 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference33rd International Conference on Computer Aided Verification, CAV 2021
CityVirtual, Online
Period20/07/2123/07/21

Funding

FundersFunder number
Amazon ARA 2020
Horizon 2020 Framework Programme639270
Blavatnik Family Foundation
European Research Council101002685
United States-Israel Binational Science Foundation2016260, 1810/18
Austrian Science FundLogiCS W1255-N23
Israel Science Foundation

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