Structure-Preserving Compilers from New Notions of Obfuscations

Matteo Campanelli, Danilo Francati*, Claudio Orlandi

*Corresponding author for this work

Research output: Contribution to book/anthology/report/proceedingArticle in proceedingsResearchpeer-review


The dream of software obfuscation is to take programs, as they are, and then generically compile them into obfuscated versions that hide their secret inner workings. In this work we investigate notions of obfuscations weaker than virtual black-box (VBB ) but which still allow obfuscating cryptographic primitives preserving their original functionalities as much as possible. In particular we propose two new notions of obfuscations, which we call oracle-differing-input obfuscation (odiO ) and oracle-indistinguishability obfuscation (oiO ). In a nutshell, odiO is a natural strengthening of differing-input obfuscation (diO ) and allows obfuscating programs for which it is hard to find a differing-input when given only oracle access to the programs. An oiO obfuscator allows to obfuscate programs that are hard to distinguish when treated as oracles. We then show applications of these notions, as well as positive and negative results around them. A few highlights include: Our new notions are weaker than VBB and stronger than diO.As it is the case for VBB, we show that there exist programs that cannot be obfuscated with odiO or oiO.Our new notions allow to generically compile several flavours of secret-key primitives (e.g., SKE, MAC, designated verifier NIZK) into their public-key equivalent (e.g., PKE, signatures, publicly verifiable NIZK) while preserving one of the algorithms of the original scheme (function-preserving), or the structure of their outputs (format-preserving).

Original languageEnglish
Title of host publicationPublic-Key Cryptography – PKC 2023 : 26th IACR International Conference on Practice and Theory of Public-Key Cryptography, Atlanta, GA, USA, May 7–10, 2023, Proceedings, Part II
EditorsAlexandra Boldyreva, Vladimir Kolesnikov
Number of pages31
Place of publicationCham
Publication dateMay 2023
ISBN (Print)978-3-031-31370-7
ISBN (Electronic)978-3-031-31371-4
Publication statusPublished - May 2023
Event26th IACR International Conference on Practice and Theory of Public-Key Cryptography, PKC 2023 - Atlanta, United States
Duration: 7 May 202310 May 2023


Conference26th IACR International Conference on Practice and Theory of Public-Key Cryptography, PKC 2023
Country/TerritoryUnited States
SeriesLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)


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