Tokai University, 2-3-23, Takanawa, Minato-ku, Tokyo, 108-8619, Japan.
National Institute of Information and Communications Technology (NICT), 4-2-1, Nukui-kitamachi, Koganei, Tokyo, 184-8795, Japan.
J Med Syst. 2019 Mar 28;43(5):128. doi: 10.1007/s10916-019-1244-2.
To provide a search functionality for encrypted data, public key encryption with keyword search (PEKS) has been widely recognized. In actual usage, a PEKS scheme should be employed with a PKE scheme since PEKS itself does not support the decryption of data. Since a naive composition of a PEKS ciphertext and a PKE ciphertext does not provide CCA security, several attempts have been made to integrate PEKS and PKE in a joint CCA manner (PEKS/PKE for short). In this paper, we further extend these works by integrating secure-channel free PEKS (SCF-PEKS) and PKE, which we call SCF-PEKS/PKE, where no secure channel is required to send trapdoors. We give a formal security definition of SCF-PEKS/PKE in a joint CCA manner, and propose a generic construction of SCF-PEKS/PKE based on anonymous identity-based encryption, tag-based encryption, and one-time signature. We also strengthen the current consistency definition according to the secure-channel free property, and show that our construction is strongly consistent if the underlying IBE provides unrestricted strong collision-freeness which is defined in this paper. We also show that such an IBE scheme can be constructed by employing the Abdalla et al. transformations (TCC 2010/J. Cryptology 2018). Finally, as an application of SCF-PEKS/PKE, we strengthen the security of encrypted Electronic Medical Record (EMR) system proposed by Guo and Yau (J. Medical Sys. 2015).
为了提供对加密数据的搜索功能，公钥加密带关键词搜索（PEKS）已被广泛认可。在实际使用中，由于 PEKS 本身不支持数据的解密，因此应使用 PKE 方案与 PEKS 结合使用。由于简单地组合 PEKS 密文和 PKE 密文不能提供 CCA 安全性，因此已经进行了几次尝试，以联合 CCA 方式集成 PEKS 和 PKE（简称 PEKS/PKE）。在本文中，我们通过集成无安全通道的安全通道免费 PEKS（SCF-PEKS）和 PKE 进一步扩展了这些工作，我们称之为 SCF-PEKS/PKE，其中不需要安全通道来发送陷门。我们以联合 CCA 的方式正式定义了 SCF-PEKS/PKE 的安全性，并基于匿名身份基加密、基于标签的加密和一次性签名提出了 SCF-PEKS/PKE 的通用构造。我们还根据无安全通道的属性加强了当前的一致性定义，并表明如果基础 IBE 提供本文中定义的不受限制的强碰撞自由性，则我们的构造是强一致的。我们还表明，可以通过采用 Abdalla 等人的变换（TCC 2010/J. Cryptology 2018）来构造这样的 IBE 方案。最后，作为 SCF-PEKS/PKE 的应用，我们加强了 Guo 和 Yau 提出的加密电子病历（EMR）系统的安全性（J. Medical Sys. 2015）。
