WEAKNESS OF PROVABLY SECURE SEARCHABLE ENCRYPTION AGAINST FREQUENCY ANALYSIS

There are encryption schemes called searchable encryption schemes. We can prove the security of these schemes based on a security model. However, we face the risk of the frequency analysis in some constructions because these schemes encrypt the keywords per word in the file as well as itself. In this attack, we assume an adversary knows the frequency distribution of plaintexts (i.e., keywords), and an adversary measures the frequency of the ciphertext and guesses the plaintext by comparing the frequency of the plaintext with it. In this work, we apply this attack to the existing works and evaluate the resistance of the searchable encryption to this attack by considering the difference between the deterministic encryption and the probabilistic encryption, and the supported types of searches.