How to Classically Verify a Quantum Cat without Killing It

Paper 2026/210

How to Classically Verify a Quantum Cat without Killing It

Yael Tauman Kalai

, Massachusetts Institute of Technology

Dakshita Khurana

, University of Illinois Urbana-Champaign, NTT Research

Justin Raizes

, NTT Research

Abstract

Existing protocols for classical verification of quantum computation (CVQC) consume the prover's witness state, requiring a new witness state for each invocation. Because QMA witnesses are not generally clonable, destroying the input witness means that amplifying soundness and completeness via repetition requires many copies of the witness. Building CVQC with low soundness error that uses only *one* copy of the witness has remained an open problem so far. We resolve this problem by constructing a CVQC that uses a single copy of the QMA witness, has negligible completeness and soundness errors, and does *not* destroy its witness. The soundness of our CVQC is based on the post-quantum Learning With Errors (LWE) assumption. To obtain this result, we define and construct two primitives (under the post-quantum LWE assumption) for non-destructively handling superpositions of classical data, which we believe are of independent interest: - A *state preserving* classical argument for NP. - Dual-mode trapdoor functions with *state recovery*.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
Keywords: Quantum Arguments
Contact author(s): yaelism @ gmail com
dakshkhurana @ gmail com
jraizes @ andrew cmu edu
History: 2026-02-11: approved; 2026-02-09: received; See all versions
Short URL: https://ia.cr/2026/210
License: CC BY

BibTeX

@misc{cryptoeprint:2026/210,
      author = {Yael Tauman Kalai and Dakshita Khurana and Justin Raizes},
      title = {How to Classically Verify a Quantum Cat without Killing It},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/210},
      year = {2026},
      url = {https://eprint.iacr.org/2026/210}
}