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Cryptographic Formula Obfuscation

  • Giovanni Di CrescenzoEmail author
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11358)

Abstract

Under intractability assumptions commonly used in cryptography, we show an efficient program obfuscator for large classes of programs, including any arbitrary monotone formula over statements expressed as equalities to a secret. Previously, only a handful set of individual functions were known to have such program obfuscators. This result has both theoretical and practical relevance. On the theoretical side, it significantly increases the class of functions that are known to have a cryptographically secure program obfuscator, and it shows that general-purpose program obfuscation results do exist with at least some level of generality, despite the likely impossibility, proved in [2], to achieve a related notion of obfuscation for any arbitrary polynomial-time program. On the practical side, there are many computational programs that can be expressed as monotone formulae over equality statements, and can now be securely obfuscated. Our most foundational contribution is a new type of obfuscation: protecting the privacy of the formula gates, and thus of much of the computation carried out by the program, in addition to the privacy of secrets used by the program. Previous program obfuscators only targeted the privacy of secrets used by the program.

Notes

Acknowledgements

Many thanks to Brian Coan for interesting discussions on these results. I am still very grateful to Alfredo De Santis, Giuseppe Persiano, and Moti Yung, coauthors in past work cited here, for several enjoyable conversations on using formula labelings in constructions of other cryptographic primitives.

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Copyright information

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Authors and Affiliations

  1. 1.Perspecta LabsBasking RidgeUSA

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