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Revisiting Witness-Succinct UC-lifting Compilers
eprint.iacr.orgpaper

Revisiting Witness-Succinct UC-lifting Compilers

The paper introduces verifiable reconstructible straightline codes (VRSCs) as an abstraction for compiling zkSNARKs into Universally Composable (UC) secure protocols. It shows that the witness-succinct UC compiler of Ganesh et al. (EUROCRYPT 2023) is missing a security requirement: permuting previously revealed evaluation openings yields a fresh accepting proof, which invalidates the claimed simulation argument. The fix uses verifier-enforced disjoint evaluation domains and a pairing-based Fischlin-style instantiation with structured Reed-Solomon codes and jointly computed KZG openings. This brings certificate generation to O(n log n) with constant extra proof size and verification work.

TL;DR Breaks the claimed UC proof of a EUROCRYPT 2023 witness-succinct zkSNARK compiler via permuted openings, and fixes it with VRSCs and disjoint evaluation domains at quasi-linear prover cost.
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Organisations named here

  • EUROCRYPT 2023
  • Fischlin transform
  • proof non-rerandomizability
  • Universal Composability
  • verifiable reconstructible straightline codes

Technologies named here

  • Reed-Solomon codes
  • KZG
  • Verifiable reconstructible straightline codes
  • Generic UC lifting theorem in terms of VRSCs
  • zkSNARK

Techniques named here

  • Fischlin-style search over authenticated codeword symbols
  • Proof non-rerandomizability as a certificate-level property

Also named here

  • Ganesh et al.

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