An efficient certificateless multi-receiver threshold decryption scheme

¹ School of Mathematical Sciences, Xiamen University, Xiamen 361005, China.
² School of Mathematical Sciences, Guizhou Normal University, Guiyang 550001, China.
³ School of Mathematical Sciences, Xinjiang Normal University, Urumqi 830017, China.

^* Corresponding author: denglunzhi@163.com

Received: 23 April 2018
Accepted: 14 January 2019

Abstract

Threshold decryption allows only quorum cooperate users to decrypt ciphertext encrypted under a public key. However, such threshold decryption scheme cannot be applied well in this situation where all users have their public and private key pairs, but do not share any private keys corresponding to the public keys, such as mobile network featured with dynamic character. The direct way to achieve threshold decryption in this case is to divide the message into several pieces and then encrypt these pieces with the public keys of different users. However, this is very inefficient. Multireceiver threshold decryption scheme that could be applied efficiently in the above situation. Recently, some certificateless (ID-based) multireceiver threshold decryption (signcryption) schemes are introduced. But the bilinear pairings are used in most of the existing schemes. In this paper, we propose an efficient certificateless threshold decryption scheme using elliptic curve cryptography (ECC) without bilinear pairing. Performance analysis shows that the proposed scheme has lower computation cost than existing some threshold decryption schemes in both encryption and decryption process. Security analysis shows that our scheme is IND-CCA secure, and no one outside of selected receivers can disclose receivers identities, against the adversaries defined in CL-PKC system under the random oracle model.