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In the paper "How to build time-lock encryption", the authors give a theoretical solution to build time-lock encryption using multi-linear based witness encryption and blockchain. However, an instantiation of the construction is unfeasible to build because of the inefficiency of multi-linear maps.

So, if witness encryption based on multi-linear maps can't provide the efficiency required for the time-lock encryption, what alternatives are there? There are witness encryption schemes built from indistinguishable obfuscation, could time-lock encryption also be implemented using that?

Ilmari Karonen
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Oiiiwk
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    I presume you mean this paper? Please always link and / or uniquely reference papers. Could you take another look at your final sentence? The first to last sentence is also incomplete. Please edit so we can reopen the question. – Maarten Bodewes May 30 '19 at 18:37
  • What makes you think, that indistinguishability obfuscation can be implemented more efficiently than multi linear maps? I think you can construct them vice versa, if you throw in fully homomorphic encryption. On a very, very rough level, it is different sides of the same coin. – tylo Jul 04 '19 at 14:49

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Time-lock puzzles can be built from indistinguishability obfuscation through succinct randomised encodings: see the work of Bitansky et al. [BGJ+,BGL+] for more details.

[BGJ+]: Bitansky et al. Time-Lock Puzzles from Randomized Encodings. ITCS'16

[BGL+]: Bitansky et al. Succinct Randomized Encodings and their Applications. STOC'15

ckamath
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