Abstract |
: |
FHE is considered to be Holy Grail of cloud computing. Many applications of cloud computing inherently need symmetric keys while very few FHE schemes have been proposed with symmetric keys. Even with the schemes based on public key cryptography a major hurdle has been the accumulation of noise in ciphertexts leading to limited size of circuits that can be evaluated using the scheme homomorphically. Noise is eliminated through refresh procedure, which has been made essentially possible with public keys containing private keys as a part. Moreover, refreshing of ciphertext is time consuming. We propose here a method of refreshing the ciphertext while not disclosing the secret key, that is, in a symmetric cryptosystem. Also, our scheme doesn’t need any evaluation key thus enabling secure delegation of data processing using such scheme. |