Cryptology ePrint Archive: Report 2017/361

Indistinguishability Obfuscation for All Circuits from Secret-Key Functional Encryption

Fuyuki Kitagawa and Ryo Nishimaki and Keisuke Tanaka

Abstract: We show that indistinguishability obfuscation (IO) for all circuits can be constructed solely from secret-key functional encryption (SKFE). In the construction, SKFE need to be able to issue a-priori unbounded number of functional keys, that is, collusion-resistant.

Our strategy is to replace public-key functional encryption (PKFE) in the construction of IO proposed by Bitansky and Vaikuntanathan (FOCS 2015) with puncturable SKFE. Bitansky and Vaikuntanathan introduced the notion of puncturable SKFE and observed that the strategy works. However, it has not been clear whether we can construct puncturable SKFE without assuming PKFE. In particular, it has not been known whether puncturable SKFE is constructed from ordinary SKFE.

In this work, we show that a relaxed variant of puncturable SKFE can be constructed from collusion-resistant SKFE. Moreover, we show that the relaxed variant of puncturable SKFE is sufficient for constructing IO.

Category / Keywords: foundations / Indistinguishability obfuscation, Secret-key functional encryption, Puncturable secret-key functional encryption

Original Publication (with major differences): IACR-EUROCRYPT-2018

Date: received 21 Apr 2017, last revised 18 Feb 2018

Contact author: kitagaw1 at is titech ac jp,ryo nishimaki@gmail com

Available format(s): PDF | BibTeX Citation

Note: Minor edits for presentation.

Version: 20180219:062629 (All versions of this report)

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