Efficient Identity-Based Encryption from LWR

Abstract

The Learning with Rounding (LWR) problem is a deterministic variant of the classical Learning with Errors (LWE) problem, for which sampling an instance does not involve discrete Gaussian sampling. We propose the first probabilistic Identity-Based Encryption (IBE) from the LWR problem which is secure in the standard model. The encryption of our IBE scheme does not require discrete Gaussian sampling as it is based on the LWR problem, and hence it is simpler and faster than that of LWE-based IBEs such as ABB scheme. We also present an efficient instantiation employing algebraic ring structure and MP12 trapdoor sampling algorithms with an implementation result. With our proposed parameter sets, the ciphertext sizes can be reduced in a large extent compared to the ABB scheme with the same security level.