Trapdoor Functions with Secure Key Leasing and Copy Protection

• URL: http://arxiv.org/abs/2609.08423v1
• Date: Tue, 08 Sep 2026 08:32:07 GMT
• Title: Trapdoor Functions with Secure Key Leasing and Copy Protection
• Abstract summary: trapdoor functions (TDFs) are fundamental primitives in public-key cryptography.<n>We first introduce the definition of TDFs with secure key leasing (TDF-SKL), which enables leasing and deleting of quantum trapdoors.<n>Next, we define TDFs with copy protection (TDF-CP), where the inversion functionality is copy protected by a quantum trapdoor.
• Score: 9.538313445597385
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Inspired by the no-cloning theorem in quantum theory, a variety of quantum cryptographic primitives with unclonable functionalities, such as secure key leasing and copy protection, have been proposed and attracted significant attention. However, trapdoor functions (TDFs), fundamental primitives in public-key cryptography, have not been extensively studied in these areas. In this work, we initiate a study of TDFs in both secure key leasing and copy protection settings. We first introduce the definition of TDFs with secure key leasing (TDF-SKL), which enables leasing and deleting of quantum trapdoors. We formalize TDF-SKL both with and without domain sampler, and give a construction of TDF-SKL without domain sampler based on the LWE assumption and a construction of TDF-SKL with domain sampler based on any standard PKE schemes combined with hinting pseudorandom generators [Koppula and Waters, CRYPTO 2019]. Next, we define TDFs with copy protection (TDF-CP), where the inversion functionality is copy protected by a quantum trapdoor. We establish a construction of TDF-CP assuming indistinguishability obfuscation and the LWE assumption, following a modular framework of copy protection proposed by Ananth and Behera [CRYPTO 2024]. We also present applications of TDF-SKL and TDF-CP. Existing constructions of public-key encryption with secure key leasing (PKE-SKL) and single-decryptor encryption (SDE) suffer from a critical vulnerability: quantum decryption keys may be destroyed after decrypting maliciously chosen ciphertexts. We construct PKE-SKL schemes and SDE schemes with robust quantum decryption keys that remain reusable after decrypting arbitrary ciphertexts from TDF-SKL and TDF-CP, respectively.

Related papers

• Send the Key in Cleartext: Halving Key Consumption while Preserving Unconditional Security in QKD Authentication [59.664950447941386]
  Quantum Key Distribution (QKD) protocols require Information-Theoretically Secure (ITS) authentication of the classical channel to preserve the unconditional security of the distilled key.<n>Since QKD requires mutual authentication, two independent one-time keys are typically consumed per round, imposing a non-trivial overhead on the net secure key rate.<n>We present a novel ITS authentication scheme based on $varepsilon$-Almost Strongly Universal$ ($varepsilon$-ASU$)
  arXiv  Detail & Related papers  (2026-03-26T14:36:05Z)
• Collusion-Resistant Quantum Secure Key Leasing Beyond Decryption [4.375194832711421]
  We present a quantum-secure collusion-resistant tracing scheme called multi-level traitor tracing (MLTT)<n>We also present a compiler that transforms an MLTT scheme for a primitive X into a collusion-resistant SKL scheme for primitive X.
  arXiv  Detail & Related papers  (2025-10-06T12:31:39Z)
• Wrangling Entropy: Next-Generation Multi-Factor Key Derivation, Credential Hashing, and Credential Generation Functions [47.715495058757824]
  We present a novel cryptanalytic technique designed to reveal pernicious leaks of entropy across multiple invocations of a cryptographic key derivation or hash function.<n>We show that it can be used to correctly identify each of the known vulnerabilities in the original MFKDF construction.<n>We propose a new construction for MFKDF2,'' a next-generation multi-factor key derivation function that can be proven to be end-to-end secure.
  arXiv  Detail & Related papers  (2025-09-07T02:01:53Z)
• Secure Multi-Key Homomorphic Encryption with Application to Privacy-Preserving Federated Learning [18.399679909318394]
  We identify a critical security vulnerability in the CDKS scheme when applied to multiparty secure computation tasks.<n>We propose a new scheme, SMHE, which incorporates a novel masking mechanism into the multi-key BFV and CKKS frameworks.<n>We implement a PPFL application using SMHE and demonstrate it provides significantly improved security with only a modest overhead in runtime evaluation.
  arXiv  Detail & Related papers  (2025-06-25T03:28:25Z)
• PKE and ABE with Collusion-Resistant Secure Key Leasing [5.5097304991439975]
  We introduce collusion-resistant security for PKE-SKL (denoted as PKE-CR-SKL)<n>In this model, the adversary can adaptively obtain multiple quantum decryption keys and access a verification oracle.<n>The size of the public key and ciphertexts must remain independent of the total number of generated quantum decryption keys.
  arXiv  Detail & Related papers  (2025-02-18T03:19:54Z)
• Secure Composition of Quantum Key Distribution and Symmetric Key Encryption [3.6678562499684517]
  Quantum key distribution (QKD) allows Alice and Bob to share a secret key over an insecure channel with proven information-theoretic security against an adversary whose strategy is bounded only by the laws of physics.<n>We consider the problem of using the QKD established key with a secure symmetric key-based encryption algorithm and use an approach based on hybrid encryption to provide a proof of security for the composition.
  arXiv  Detail & Related papers  (2025-01-14T20:58:02Z)
• A Simple Framework for Secure Key Leasing [10.04587045407742]
  Key-revocable cryptography enables us to lease a cryptographic key as a quantum state in such a way that the key can be later revoked in a verifiable manner.<n>We propose a simple framework for constructing cryptographic primitives with secure key leasing via the certified deletion property of BB84 states.
  arXiv  Detail & Related papers  (2024-10-04T13:24:03Z)
• CodeChameleon: Personalized Encryption Framework for Jailbreaking Large Language Models [49.60006012946767]
  We propose CodeChameleon, a novel jailbreak framework based on personalized encryption tactics. We conduct extensive experiments on 7 Large Language Models, achieving state-of-the-art average Attack Success Rate (ASR) Remarkably, our method achieves an 86.6% ASR on GPT-4-1106.
  arXiv  Detail & Related papers  (2024-02-26T16:35:59Z)
• Publicly-Verifiable Deletion via Target-Collapsing Functions [81.13800728941818]
  We show that targetcollapsing enables publiclyverifiable deletion (PVD) We build on this framework to obtain a variety of primitives supporting publiclyverifiable deletion from weak cryptographic assumptions.
  arXiv  Detail & Related papers  (2023-03-15T15:00:20Z)
• Revocable Cryptography from Learning with Errors [61.470151825577034]
  We build on the no-cloning principle of quantum mechanics and design cryptographic schemes with key-revocation capabilities. We consider schemes where secret keys are represented as quantum states with the guarantee that, once the secret key is successfully revoked from a user, they no longer have the ability to perform the same functionality as before.
  arXiv  Detail & Related papers  (2023-02-28T18:58:11Z)
• Backflash Light as a Security Vulnerability in Quantum Key Distribution Systems [77.34726150561087]
  We review the security vulnerabilities of quantum key distribution (QKD) systems. We mainly focus on a particular effect known as backflash light, which can be a source of eavesdropping attacks.
  arXiv  Detail & Related papers  (2020-03-23T18:23:12Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.