Paper 2020/235

Statistical Zaps and New Oblivious Transfer Protocols

Vipul Goyal, Abhishek Jain, Zhengzhong Jin, and Giulio Malavolta


We study the problem of achieving statistical privacy in interactive proof systems and oblivious transfer -- two of the most well studied two-party protocols -- when limited rounds of interaction are available. Statistical Zaps: We give the first construction of statistical Zaps, namely, two-round statistical witness-indistinguishable (WI) protocols with a public-coin verifier. Our construction achieves computational soundness based on the quasi-polynomial hardness of learning with errors. Three-Round Statistical Receiver-Private Oblivious Transfer: We give the first construction of a three-round oblivious transfer (OT) protocol -- in the plain model -- that achieves statistical privacy for receivers and computational privacy for senders against malicious adversaries, based on polynomial-time assumptions. The round-complexity of our protocol is optimal. We obtain our first result by devising a public-coin approach to compress sigma protocols, without relying on trusted setup. To obtain our second result, we devise a general framework via a new notion of statistical hash commitments that may be of independent interest.

Available format(s)
Cryptographic protocols
Publication info
A major revision of an IACR publication in EUROCRYPT 2020
ZapsOblivious Transfer
Contact author(s)
vipul @ cmu edu
abhishek @ cs jhu edu
zjin12 @ jhu edu
giulio malavolta @ hotmail it
2020-02-24: received
Short URL
Creative Commons Attribution


      author = {Vipul Goyal and Abhishek Jain and Zhengzhong Jin and Giulio Malavolta},
      title = {Statistical Zaps and New Oblivious Transfer Protocols},
      howpublished = {Cryptology ePrint Archive, Paper 2020/235},
      year = {2020},
      note = {\url{}},
      url = {}
Note: In order to protect the privacy of readers, does not use cookies or embedded third party content.