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SUMMARY:Zero-Knowledge in Streaming Interactive Proofs - Tomer Gewirtzman 
 (Technion)
DTSTART:20250225T140000Z
DTEND:20250225T150000Z
UID:TALK227749@talks.cam.ac.uk
CONTACT:Tom Gur
DESCRIPTION:In a recent work\, Cormode\, Dall'Agnol\, Gur and Hickey (CCC\
 , 2024) introduced the model of Zero-Knowledge Streaming Interactive Proof
 s (zkSIPs). Loosely speaking\, such proof-systems enable a prover to convi
 nce a streaming verifier that the input x\, to which it has read-once stre
 aming access\, satisfies some property\, in such a way that nothing beyond
  the correctness of the claim is revealed. Cormode et al. also gave constr
 uctions of zkSIPs to some specific and notable problems of interest. In th
 is work\, we advance the study of zero-knowledge proofs in the streaming m
 odel\, by presenting protocols that are significantly more general and mor
 e secure. We use a definition of zero-knowledge that is a variation of tha
 t used by Cormode et al.\, which we find more appealing but is technically
  incomparable. Our main result is a zkSIP for any NP relation\, that can b
 e decided by low-depth polynomial-size circuits. We emphasize that this is
  the first general purpose protocol in this model\, which captures\, as a 
 special case\, the problems considered by the prior work. We also construc
 t a specialized protocol for the ``polynomial evaluation'' problem conside
 red in that work\, with improved parameters. The protocols constructed by 
 Cormode et al. have an inverse polylogarithmic simulation error (i.e.\, a 
 gap with which a bounded-space distingiusher can distinguish the simulatio
 n from a real execution). This means that their protocols are entirely ins
 ecure if run multiple times (say on different inputs). In contrast\, our p
 rotocols achieve a negligible zero-knowledge error\, a stronger and far mo
 re robust security guarantee.
LOCATION:Computer Laboratory\, William Gates Building\, Room SS03
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