By leveraging the no-cloning principle of quantum mechanics, unclonable cryptography enables us to achieve novel cryptographic protocols that are otherwise impossible classically. Two most notable examples of unclonable cryptography are quantum copy-protection and unclonable encryption. Despite receiving a lot of attention in recent years, two important open questions still remain: copy-protection for point functions in the plain model, which is usually considered as feasibility demonstration, and unclonable encryption with unclonable indistinguishability security in the plain model. In this work, by relying on previous works of Coladangelo, Liu, Liu, and Zhandry (Crypto'21) and Culf and Vidick (Quantum'22), we establish a new monogamy-of-entanglement property for subspace coset states, which allows us to obtain the following new results: - We show that copy-protection of point functions exists in the plain model, with different challenge distributions (including arguably the most natural ones). - We show, for the first time, that unclonable encryption with unclonable indistinguishability security exists in the plain model.

翻译：利用量子力学的不可克隆原理，不可克隆密码学使我们能够实现经典方法无法实现的新型密码协议。其中两个最显著的例子是量子复制保护和不可克隆加密。尽管近年来受到广泛关注，但仍有两个重要的开放问题：普通模型中点函数的复制保护（通常被视为可行性证明），以及普通模型中具有不可克隆不可区分安全性的不可克隆加密。本文基于Coladangelo、Liu、Liu和Zhandry（Crypto'21）以及Culf和Vidick（Quantum'22）的先前工作，建立了子空间陪集态的新单配性纠缠性质，从而获得以下新结果：- 我们证明，在普通模型中存在针对不同挑战分布（包括最自然的分布）的点函数复制保护。- 我们首次证明，在普通模型中存在具有不可克隆不可区分安全性的不可克隆加密。