Cryptology ePrint Archive: Report 2015/482

Extractable Witness Encryption and Timed-Release Encryption from Bitcoin

Jia Liu and Saqib A. Kakvi and Bogdan Warinschi

Abstract: We propose a new witness encryption based on Subset-Sum which achieves extractable security without relying on obfuscation and is more efficient than the existing ones. Our witness encryption employs multilinear maps of arbitrary order and it is independent of the implementations of multilinear maps. As an application, we construct a new timed-release encryption based on the Bitcoin protocol and extractable witness encryption. The novelty of our scheme is that the decryption key will be automatically revealed in the bitcoin block-chain when the block-chain reaches a certain length.

Category / Keywords: timed-release encryption, Bitcoin, proof-of-work, witness encryption, SAT, Subset-Sum, multilinear maps, extractability

Date: received 20 May 2015, last revised 10 Feb 2016

Contact author: lovelykitoun at gmail com

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Version: 20160210:190212 (All versions of this report)

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