Obfustopia Built on Secret-Key Functional Encryption
Obfustopia Built on Secret-Key Functional Encryption
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DOI：
10.1007/978-3-319-78375-8_20
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发表时间：
2018-04
影响因子：
3
通讯作者：
Fuyuki Kitagawa;R. Nishimaki;Keisuke Tanaka
中科院分区：
文献类型：
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作者：
Fuyuki Kitagawa;R. Nishimaki;Keisuke Tanaka
我们表明，所有电路的不可否认性混淆（IO）可以单独从密钥功能加密（SKFE）。在构造中，SKFE需要能够发出先验无界数量的功能密钥，即抗合谋。我们的策略是在Bitansky和Vaikuntanathan（FOCS 2015）提出的IO构造中用可穿孔的SKFE取代公钥函数加密（PKFE）。Bitansky和Vaikuntanathan引入了可穿孔SKFE的概念，并观察到该策略有效。然而，它还不清楚，我们是否可以构造可穿孔SKFE没有假设PKFE。特别是，它还不知道是否可穿孔SKFE构造从普通SKFE。在这项工作中，我们表明，一个宽松的变种可穿刺SKFE可以构建抗共谋SKFE。此外，我们还证明了可删截SKFE的松弛变体是构造IO的充分条件。此外，我们还研究了SKFE的抗共谋性与简洁性之间的关系。如果函数加密的加密电路的大小与函数的大小呈次线性关系，则称函数加密是弱简洁的。我们证明了仅支持一个功能键的弱简洁SKFE可以构造出抗共谋的SKFE，结合上述两个结果，我们证明了所有电路的IO都可以由仅支持一个功能键的弱简洁SKFE构造出.
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) withpuncturable 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.In addition, we also study the relation of collusion-resistance and succinctness for SKFE. Functional encryption is said to be weakly-succinct if the size of its encryption circuit is sub-linear in the size of functions. We show that collusion-resistant SKFE can be constructed from weakly-succinct SKFE supporting only one functional key.By combining the above two results, we show that IO for all circuits can be constructed from weakly-succinct SKFE supporting only one functional key.