Quantum Fire with Delegated Cloning

2026-10-02

AI Summary

This study addresses the issues of uncontrollable delegation and the absence of access control in quantum fire primitives by proposing a delegatable quantum fire scheme. The work introduces the first key-based cloning delegation mechanism, designing indivisible and abuse-resistant quantum torch keys. By integrating a classical oracle model with quantum superposition query techniques, the scheme achieves fine-grained access control over quantum states. Security proofs demonstrate that an adversary can only leverage a limited number of torches to provide cloning services for a correspondingly bounded number of independent parties. This research effectively resolves the challenge of uncontrolled permissions in quantum fire constructions, establishing a new paradigm for access control in quantum cryptography.

Abstract

Quantum fire is a recently introduced cryptographic primitive consisting of efficiently preparable quantum states, called \emph{flames}, that admit efficient cloning but resist efficient telegraphing, namely reconstruction via classical communication without preshared entanglement. In all prior constructions of quantum fire, cloning is a public operation that requires no separate key and every holder of a flame state can clone it. For applications to access control, however, an issuer may wish to delegate cloning to designated quantum servers while withholding this capability from other flame holders. To address this, we introduce \emph{delegatable quantum fire}, in which cloning requires a separate key. We give two constructions in the classical-oracle model. Our first construction uses a classical secret key which enables cloning, and any user with the entire key may clone successfully. Our second construction, which we call \emph{torch-fire}, uses quantum cloning keys, called \emph{torches}, which enable cloning while remaining unaffected in the process but cannot otherwise be split or delegated to enable additional cloning. An efficient adversary given $m$ torches cannot, except with negligible probability, enable more than $m$ noncommunicating parties to each clone a fresh, independently issued challenge flame. The adversary may jointly process its resources before separating the parties and distribute arbitrarily entangled registers among them. Both constructions are in the oracle model, relying on public classical oracles that allow queries in quantum superposition.

Problem

• quantum fire
• delegated cloning
• access control
• quantum cryptography

Innovation

• Delegatable Quantum Fire
• Torch-fire
• Quantum Cloning Keys
• Classical Oracle Model
• Anti-telegraphing