论文标题
量子拷贝保护的无容易被解密者
Uncloneable Decryptors from Quantum Copy-Protection
论文作者
论文摘要
不可统治的解密者是加密方案（带有经典的明文和密文），其附加功能的功能是推导不可拨款的量子状态（称为解密者），可用于在不了解秘密钥匙的情况下解密密码（Georgiou and Zhandry and Zhandry和Zhandry，iacr'20）。我们在计算环境中研究了不可统的解密者，并提供了越来越强的安全性概念，这些概念扩展了对称加密的各种难以区分的安全性概念。 我们表明，可以从复制保护方案（Aaronson，CCC'09）实例化CPA安全的无倾斜位解密，以实例化任何平衡的二进制功能。我们引入了一个新的Flip检测安全性概念，以启发出受加密方案的左或右安全性概念启发的复制保护方案，并证明它可以用于实例化CPA安全不可撤销的解密者，以获取无限制长度的消息。 然后，我们展示了如何使用强大的EUF-CMA安全数字签名来增强不可转让的解密者对CCA2安全性的CPA安全性。我们表明，我们的构造可以相对于[AAR09]中使用的量子甲骨文进行实例化，也可以是（Aaronson等，Crypto'21）中使用的经典甲骨文来实例化复制保护方案。我们的构造是在对称设置中第一个实现CPA或CCA2安全性的构造。
Uncloneable decryptors are encryption schemes (with classical plaintexts and ciphertexts) with the added functionality of deriving uncloneable quantum states, called decryptors, which could be used to decrypt ciphers without knowledge of the secret key (Georgiou and Zhandry, IACR'20). We study uncloneable decryptors in the computational setting and provide increasingly strong security notions which extend the various indistinguishable security notions of symmetric encryption. We show that CPA secure uncloneable bit decryptors could be instantiated from a copy protection scheme (Aaronson, CCC'09) for any balanced binary function. We introduce a new notion of flip detection security for copy protection schemes inspired by the notions of left or right security for encryption schemes, and show that it could be used to instantiate CPA secure uncloneable decryptors for messages of unrestricted length. We then show how to strengthen the CPA security of uncloneable decryptors to CCA2 security using strong EUF-CMA secure digital signatures. We show that our constructions could be instantiated relative to either the quantum oracle used in [Aar09] or the classical oracle used in (Aaronson et al., CRYPTO'21) to instantiate copy protection schemes. Our constructions are the first to achieve CPA or CCA2 security in the symmetric setting.
