Abstract
We present a positive obfuscation result for a traditional cryptographic functionality. This positive result stands in contrast to well-known impossibility results (Barak et al. in Advances in Cryptology—CRYPTO’01, 2002), for general obfuscation and recent impossibility and implausibility (Goldwasser and Kalai in 46th IEEE Symposium on Foundations of Computer Science (FOCS), pp. 553–562, 2005) results for obfuscation of many cryptographic functionalities.
Whereas other positive obfuscation results in the standard model apply to very simple point functions (Canetti in Advances in Cryptology—CRYPTO’97, 1997; Wee in 37th ACM Symposium on Theory of Computing (STOC), pp. 523–532, 2005), our obfuscation result applies to the significantly more complex and widely-used re-encryption functionality. This functionality takes a ciphertext for message m encrypted under Alice’s public key and transforms it into a ciphertext for the same message m under Bob’s public key.
To overcome impossibility results and to make our results meaningful for cryptographic functionalities, our scheme satisfies a definition of obfuscation which incorporates more security-aware provisions.
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Communicated by Cynthia Dwork
This paper was solicited by the Editors-in-Chief as one of the best papers from TCC 2007, based on the recommendation of the program committee.
Research partially performed at IBM Zurich Research Laboratory, Switzerland and partially supported by NSF grant CNS-0716142 and a Microsoft New Faculty Fellowship.
Research partially performed while at MIT, and supported by NSF Grants CCF-0635297, CCF-0832797 and by a Computing Innovation Fellowship.
Research partially performed at IBM Zurich Research Laboratory, Switzerland and partially supported by NSF grant CNS-0845811.
Research performed while at MIT, and supported by NSF grant CNS-0430450 and NSF grant CFF-0635297.
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Hohenberger, S., Rothblum, G.N., Shelat, A. et al. Securely Obfuscating Re-Encryption. J Cryptol 24, 694–719 (2011). https://doi.org/10.1007/s00145-010-9077-7
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DOI: https://doi.org/10.1007/s00145-010-9077-7