Deterministic identity-based encryption from lattices with more compact public parameters

Abstract

Xie et al. (SCN 2012) proposed the first deterministic identity-based encryption (DIBE) scheme with an adaptive security in the auxiliary-input setting, under the learning with errors (LWE) assumption. However, the master public key consists of O(λ) number of basic matrices. In this paper, we consider to construct adaptively secure DIBE schemes from partitioning functions (IACR’17). By instantiating the DIBE construction with two partitioning functions, we get two DIBE schemes in which the master public key consists of O(log 3λ) (respectively, O(log 2λ)) number of basic matrices in the first (respectively, the second) DIBE scheme.We also change the identity-based encryption (IBE) scheme of Yamada16 (Eurocrypt’16) to construct DIBE scheme with the same security from the LWE problem. And the master public key consists of O(λ1/d) number of basic matrices, where d≥ 2 is a flexible integer.