DOI: 10.3724/SP.J.1146.2013.00300

Journal of Electronics & Information Technology (电子与信息学报) 2013/35:12 PP.2999-3004

A Key Recovery Attack on Fully Homomorphic Encryption Scheme

Fully Homomorphic Encryption (FHE) makes it possible to perform all sorts of calculation in cipher domain, and own great value in cloud computing. However, the security of existing FHE schemes under the non-adaptive chosen-ciphertext attacks remains an issue to be studied. In this paper the construction of the Learning With Errors-based FHE scheme is analyzed, and it is pointed out that this cryptosystem has a potential security flaw, which creates the risk of private key leakage when confronting non-adaptive chosen cipher attacks. According to this, a key recovery attack is proposed, which is capable of recovering the private keys of such cryptosystem with the help of decryption oracle, through blending the dichotomy approximation in cipher domain and the solution of linear congruent equations.

Key words:Fully Homomorphic Encryption (FHE),Key recovery attack,Learning With Errors (LWE) issues,Dichotomy approximation,Linear congruent equations

ReleaseDate:2014-07-21 17:01:13