Study On Identity-Based Encryption With Dual Trapdoor Keyword Search

With the development of cloud computing, the security issues of cloud computing become one of the important factors that restricts its development. In order to protect the security of data, users usually adopt encryption schemes to encrypt. However, since the use of traditional encryption scheme to encrypt will reduce the availability of data. And make it difficult to operation on encrypted data. Therefore, how to improve data availability in the premise of ensuring data confidentiality, become a hot research topic in cryptography.Searchable encryption allows data owner to encrypt his/her data and generate a search trapdoor to search on the encrypted data. Identity-based encryption with keyword search(IBEKS) is searchable encryption primitive in identity-based setting. In an IBEKS scheme, users’ private keys are generated by the authority, private key generator(PKG), according to their identities. User or someone else can use his/her identity to encrypt data and store it in a cloud storage server. At later, he/she can use his/her private key to produce a search trapdoor which represented a keyword and send it to the cloud storage server. The cloud storage server can use this trapdoor to test whether the user’s encrypted data contains the corresponding keyword. Existing IBEKS schemes only focus on supporting efficient and complex queries for the data owners, but never consider the PKG’s capacity to efficiently search the encrypted data. However, in some scenarios, it may require the private key generator to efficiently search the encrypted data intended for all users. For the above problem, in this paper, we introduce a new primitive named Identity-Based Encryption with Dual Trapdoor Keyword Search(IBEDTKS). In this primitive, the user can use his/her own private key to generate a keyword trapdoor to search. Furthermore, the PKG can produce a peculiar trapdoor to search all users’ encrypted data. We formally present the definition and security model for Identity-Based Encryption with Dual Trapdoor Keyword Search. Based on composite order bilinear groups, we propose a concrete IBEDTKS construction, and prove it in standard model. We also implement the proposed construction using the Java language. The experimental results show that our construction is efficient.