A Unified Framework of Homomorphic Encryption for Multiple Parties with Non-Interactive Setup

To solve authority issue of standard (single-key) HE, variants of HE have emerged in the context of multiple parties resulting in the development of two different lines of HE schemes – Multi-Party HE (MPHE) and Multi-Key HE (MKHE). In this paper, we propose a new HE primitive, called Multi-Group HE (MGHE). Stated informally, an MGHE scheme provides seamless integration between MPHE and MKHE, and combines the best of both these primitives. In addition, we construct the first MPHE scheme that features a non-interactive key generation by refactoring the evaluation key to be nearly linear, allowing it to be computed by simple summation.