Certificateless public key encryption with keyword search

Public Key Encryption with Keyword Search (PEKS), an indispensable part of searchable encryption, is stock-in-trade for both protecting data and providing operability of encrypted data. So far most of PEKS schemes have been established on Identity-Based Cryptography (IBC) with key escrow problem inherently. Such problem severely restricts the promotion of IBC-based Public Key Infrastructure including PEKS component. Hence, Certifcateless Public Key Cryptography (CLPKC) is efficient to remove such problem. CLPKC is introduced into PEKS, and a general model of Certifcateless PEKS (CLPEKS) is formalized. In addition, a practical CLPEKS scheme is constructed with security and efficiency analyses. The proposal is secure channel free, and semantically secure against adaptive chosen keyword attack and keyword guessing attack. To illustrate the superiority, massive experiments are conducted on Enron Email dataset which is famous in information retrieval field. Compared with existed constructions, CLPEKS improves the efficiency in theory and removes the key escrow problem.