论文标题
建设性密码学中的互动性：建模和应用到可更新的加密和私人信息检索
Interactivity in Constructive Cryptography : Modeling and Applications to Updatable Encryption and Private Information Retrieval
论文作者
论文摘要
在这项工作中，我们扩展了Maurer在2011年引入的建设性密码学（CC）框架，以处理交互式协议。 我们设计并构建了所谓的{\ em Interactive Server Memory资源}（ISMR），它是CC中客户端服务器协议的基本实例的增强版本，即服务器存储器资源。然后，我们将ISMR构造应用于远程存储的两种类型的交互式加密协议：可更新加密（UE）和私人信息检索（PIR）。 关于UE，我们的结果是这些协议的可组合版本，阐明了{\ em Any} UE方案实现的安全保证。也就是说，我们给出相关的安全概念，根据给定的泄漏环境考虑。让USMR表示我们的ISMR适用于UE应用程序，我们证明$ \ Mathsf {ind} \ text { - } \ Mathsf {ue} \ text { - } \ Mathsf {cpa} $ Security足以实现Ciperext的安全结构，以实现安全结构。和$ \ mathsf {ind} \ text { - }（\ Mathsf {engsf {eng}+\ Mathsf {wist}）\ text { - } \ Mathsf {cpa} $安全性就足以在不受限制地泄漏的情况下进行机密USMR的安全构造。结果，与以前所主张的相反，$ \ mathsf {ind} \ text { - } \ mathsf {ue} $安全概念并不总是比$ \ mathsf {indsf {indsf {indsf {indsf {indsf {indsf { - text { - }（\ sathsf {encf+wimd}）$一个。 关于PIR，我们还提供了PIR协议的可组合版本，产生了一个独特的模型，该模型统一了PIR的不同概念：IT-PIR，C-PIR，One或Multi-Server Pir。使用CC的灵活性，我们还能够对PIR变体进行建模，例如Spir。
In this work, we extend the Constructive Cryptography (CC) framework introduced by Maurer in 2011 so as to handle interactive protocols. We design and construct a so-called {\em Interactive Server Memory Resource} (ISMR), that is an augmented version of the basic instantiation of a client-server protocol in CC, namely the Server Memory Resource. We then apply our ISMR construction to two types of interactive cryptographic protocols for remote storage : Updatable Encryption (UE) and Private Information Retrieval (PIR). Concerning UE, our results are a composable version of those protocols, clarifying the security guarantees achieved by {\em any} UE scheme. Namely, we give the relevant security notion to consider according to a given leakage context. Letting USMR denote our ISMR adapted to the UE application, we prove that $\mathsf{IND}\text{-}\mathsf{UE}\text{-}\mathsf{CPA}$ security is sufficient for a secure construction of a confidential USMR that hides the age of ciphertexts; and $\mathsf{IND}\text{-}(\mathsf{ENC}+\mathsf{UPD})\text{-}\mathsf{CPA}$ security is sufficient for a secure construction of a confidential USMR in case of unrestricted leakage. As a consequence, contrary to what was claimed before, the $\mathsf{IND}\text{-}\mathsf{UE}$ security notion is not always stronger than the $\mathsf{IND}\text{-}(\mathsf{ENC+UPD})$ one. Concerning PIR, we also give a composable version of PIR protocols, yielding a unique model that unifies different notions of PIR : IT-PIR, C-PIR, one- or multi- server PIR. Using the flexibility of CC, we are also able to model PIR variants, such as SPIR.
