Blockchain-assisted Public-key Encryption with Keyword Search against Keyword Guessing Attacks for Cloud Storage
The main aim of this project is to provide a secure PEKS scheme against Keyword Guessing Attack.
Public key encryption with keyword search(PEKS) is a cryptographic primitive that address the security issues in data confidentiality. Here both the data and keywords are encrypted under receivers public key and decrypted under users private key.The user can retrieve the data by searching the keywords, if it matches the encrypted keywords stored in the index it allows further process.Since searched data(eg., email with sensitive words) is kept highly secret by many individuals and organizations. Since the keyword are low entropy, it is vulnerable to keyword guessing attack.
In this paper we present a secure and efficient PEKS scheme called SEPSE to thwart both off-line and online KGA for secure cloud storage. In SEPSE it resist off-line KGA without the single-point-of-failure problem, where multiple dedicated key servers are employed to assist users in encrypting keywords without learning any information about the keywords. SEPSE supports key renewal on key servers so as to fight against the key compromise and provides a stronger security guarantee. We present a block chain assisted rate-limiting mechanism and integrate it into SEPSE to resist online KGA, where each request of servers-derived keyword made by the user is integrated into a transaction on a public block chain.