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Lattice-Based Quantum Advantage from Rotated Measurements

Yusuf Alnawakhtha, Atul Mantri, Carl A. Miller, Daochen Wang

TL;DR

A new technique that uses the entire range of qubit measurements from the XY-plane and shows an optimized two-round proof of quantumness whose security can be expressed directly in terms of the hardness of the LWE (learning with errors) problem.

Abstract

Trapdoor claw-free functions (TCFs) are immensely valuable in cryptographic interactions between a classical client and a quantum server. Typically, a protocol has the quantum server prepare a superposition of two-bit strings of a claw and then measure it using Pauli-$X$ or $Z$ measurements. In this paper, we demonstrate a new technique that uses the entire range of qubit measurements from the $XY$-plane. We show the advantage of this approach in two applications. First, building on (Brakerski et al. 2018, Kalai et al. 2022), we show an optimized two-round proof of quantumness whose security can be expressed directly in terms of the hardness of the LWE (learning with errors) problem. Second, we construct a one-round protocol for blind remote preparation of an arbitrary state on the $XY$-plane up to a Pauli-$Z$ correction.

Lattice-Based Quantum Advantage from Rotated Measurements

TL;DR

A new technique that uses the entire range of qubit measurements from the XY-plane and shows an optimized two-round proof of quantumness whose security can be expressed directly in terms of the hardness of the LWE (learning with errors) problem.

Abstract

Trapdoor claw-free functions (TCFs) are immensely valuable in cryptographic interactions between a classical client and a quantum server. Typically, a protocol has the quantum server prepare a superposition of two-bit strings of a claw and then measure it using Pauli- or measurements. In this paper, we demonstrate a new technique that uses the entire range of qubit measurements from the -plane. We show the advantage of this approach in two applications. First, building on (Brakerski et al. 2018, Kalai et al. 2022), we show an optimized two-round proof of quantumness whose security can be expressed directly in terms of the hardness of the LWE (learning with errors) problem. Second, we construct a one-round protocol for blind remote preparation of an arbitrary state on the -plane up to a Pauli- correction.
Paper Structure (29 sections, 23 theorems, 104 equations, 15 figures)

This paper contains 29 sections, 23 theorems, 104 equations, 15 figures.

Key Result

Theorem 1.1

Let $\lambda$ denote the security parameter. Suppose that $n, m, q, \sigma, \tau$ are functions of $\lambda$ that satisfy the constraints given in fig:parameters from sec:prelim, and suppose that the $\textnormal{LWE}_{n,q,G ( \sigma, \tau )}$ problem is hard. Then, there exists a two round interact

Figures (15)

  • Figure 1: Parameters and assumptions.
  • Figure 2: The single-bit public-key encryption algorithm $K$. $pk$ is the public key, $s$ is the secret key, $b$ is the message, and $ct$ is the ciphertext.
  • Figure 3: The single-bit public-key encryption algorithm $J$.
  • Figure 4: The proof of quantumness protocol, including the behavior of the verifier (Alice).
  • Figure 5: The behavior of an honest quantum prover in Protocol Q in \ref{['fig:pfprot']}.
  • ...and 10 more figures

Theorems & Definitions (45)

  • Theorem 1.1: Informal
  • Theorem 1.2: Informal
  • Lemma 3.1: Corollary 9 of canonne2020gaussian
  • Proposition 3.2
  • Proposition 3.3
  • proof
  • Proposition 3.4
  • proof
  • Proposition 3.5
  • Definition 4.1: Generalized GHZ state
  • ...and 35 more