Fully Homomorphic Encryption Scheme without Key Switching

Abstract

We present a fully homomorphic encryption (FHE) scheme without key switching based on ring-learning with errors (RLWE) problems and some other assumption. Previous FHE schemes based on LWE needed a step called key switching to reduce the dimension of ciphertext. The key switching step actually needs a heavy computation and severe increasement of keys. So the key switching step is a big burden for implementing FHE Schemes. We suggest a FHE scheme without key switching step by reducing the dimension of ciphertexts in other way. Instead of throwing away key switching, we need another hardness assumption of the difficulty of solving quadratic equation over rings.

New Fluctuation Functions to Measure Spatial Correlation of Encrypted Images in Reversible Data Hiding

“…A fully homomorphic encryption method without key switching was proposed to reduce the complexity [9] . properties.…”