Batching Base Oblivious Transfers

Ian McQuoid; Mike Rosulek; Lawrence Roy

Paper 2021/682 Original: eprint.iacr.org/2021/682 ↗

Batching Base Oblivious Transfers

Ian McQuoid

Mike Rosulek

Lawrence Roy

Abstract

Protocols that make use of oblivious transfer (OT) rarely require just one instance. Usually a batch of OTs is required --- notably, when generating base OTs for OT extension. There is a natural way to optimize 2-round OT protocols when generating a batch, by reusing certain protocol messages across all instances. In this work we show that this batch optimization is error-prone. We catalog many implementations and papers that have an incorrect treatment of this batch optimization, some of them leading to catastrophic leakage in OT extension protocols. We provide a full treatment of how to properly optimize recent 2-round OT protocols for the batch setting. Along the way we show several performance improvements to the OT protocol of McQuoid, Rosulek, and Roy (ACM CCS 2020). In particular, we show an extremely simple OT construction that may be of pedagogical interest.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
History: 2021-05-25: last updated; 2021-05-25: published
Short URL: https://ia.cr/2021/682
License: https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2021/682,
      author = {Ian McQuoid and Mike Rosulek and Lawrence Roy},
      title = {Batching Base Oblivious Transfers},
      howpublished = {Cryptology {ePrint} Archive, Paper 2021/682},
      year = {2021},
      url = {https://eprint.iacr.org/2021/682}
}