Cryptology ePrint Archive: Report 2019/904

Timed-Release Encryption With Master Time Bound Key (Full Version)

Gwangbae Choi and Serge Vaudenay

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.

Category / Keywords: public-key cryptography / timed-release encryption, Weil pairing, bilinear Diffie-Hellman problem

Original Publication (with minor differences): WISA 2019

Date: received 5 Aug 2019, last revised 5 Aug 2019

Contact author: gwangbae choi at epfl ch, serge vaudenay@epfl ch

Available format(s): PDF | BibTeX Citation

Version: 20190808:063813 (All versions of this report)

Short URL: ia.cr/2019/904