Private balance-checking on blockchain accounts using private integer addition

Birenjith Sasidharan, Emanuele Viterbo

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


A transaction record in a sharded blockchain can be represented as a two-dimensional array of integers with row-index associated to an account, column-index to a shard and the entry to the transaction amount. In a blockchain-based cryptocurrency system with coded sharding, a transaction record of a given epoch of time is encoded using a maximum-distance-separable code considering the entries as finite-field symbols. Each column of the resultant coded array is then stored in a server. In this paper, we propose a privacy-preserving multi-round protocol that allows a remote client to retrieve from a coded blockchain system the sum of transaction amounts belonging to two different epochs of time, but to the same ac-count. At the core of the protocol lies an algorithm for a remote client to privately compute a non-linear function referred to as integer addition of two finite-field symbols representing integer numbers, in the presence of curious-but-honest adversaries. Applying it to balance-checking in a cryptocurrency system, the protocol guarantees information-theoretic privacy on account number and shard number thereby ensuring perfect user anonymity, and also maintains confidentiality of half of the input bits on average. The protocol turns out to be a useful primitive for balance-checking in lightweight clients of a PolyShard-ed blockchain.

Original languageEnglish
Title of host publication2022 IEEE International Symposium on Information Theory, ISIT 2022
EditorsMuriel Médard, Mikael Skoglund, Aylin Yener
Place of PublicationPiscataway NJ USA
PublisherIEEE, Institute of Electrical and Electronics Engineers
Number of pages6
ISBN (Electronic)9781665421591
ISBN (Print)9781665421607
Publication statusPublished - 2022
EventIEEE International Symposium on Information Theory 2022 - Espoo, Finland
Duration: 26 Jun 20221 Jul 2022 (Proceedings) (Website)

Publication series

NameIEEE International Symposium on Information Theory - Proceedings
PublisherIEEE, Institute of Electrical and Electronics Engineers
ISSN (Print)2157-8095
ISSN (Electronic)2157-8117


ConferenceIEEE International Symposium on Information Theory 2022
Abbreviated titleISIT 2022
Internet address

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