Timed-Release Encryption With Master Time Bound Key (Extended)

Gwangbae Choi⁺ and Serge Vaudenay

Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

{gwangbae.choi, serge.vaudenay}@epfl.ch

Abstract

Timed-release encryption allows senders to send a message to a receiver which cannot decrypt until a server releases a time bound key at the release time. The release time usually supposed to be known to the receiver, the ciphertext therefore cannot be decrypted if the release time is lost. We solve this problem in this paper by having a master time bound key which can replace the time bound key of any release time. We first present security models of the timed-release encryption with master time bound key. We present a provably secure construction based on the Weil pairing. We also propose the parameters for our construction by security levels. At the end, we implement our construction and show its performance by using the parameters that we proposed.

Keywords: Timed-release encryption, Weil pairing, Bilinear Diffie-Hellman problem.

+: Corresponding author: Gwangbae Choi
LASEC - Security and Cryptography Laboratory, Ecole Polytechnique F´ed´erale de Lausanne, 1015 Lausanne, Switzeralnd, Tel: +41 21 693 47 04

Journal of Wireless Mobile Networks, Ubiquitous Computing, and Dependable Applications (JoWUA)

Vol. 10, No. 4, pp.88-108, December 2019 [pdf]

Received: November 23, 2019; Accepted: December 10, 2019; Published: December 31, 2019
DOI: 10.22667/JOWUA.2019.12.31.088