Identity-based Searchable Encryption Scheme for Encrypted Email System

In encrypted email system, the public key searchable encryption technology can effectively solve the problem of searching for encrypted emails without decryption. In view of the complex key management problem of public key searchable encryption, an identity-based cryptosystem is introduced in the encrypted mail system. For the offline keyword guessing attack problem of searchable encryption, the method of encrypting keywords and generating trapdoors are adopted at the same time, and the server is designated to search for encrypted emails. At the same time, under the random oracle model, based on the decisional bilinear Diffie-Hellman assumption, the scheme is proved to satisfy the trapdoor and ciphertext indistinguishable security. The numerical experiments show that the scheme has higher computational efficiency than the existing schemes in the keyword trapdoor generation and keyword ciphertext test phase.