In this work, we initiate the study of post-zeroizing obfuscation, and we present a construction for the special case of evasive functions. We show that our obfuscator survives all known attacks on the underlying multilinear maps, by proving that no encodings of 0 can be created by a generic-model adversary. Previous obfuscators (for both evasive and general functions) were either analyzed in a less-conservative “pre-zeroizing” model that does not capture recent attacks, or were proved secure relative to assumptions that are now known to be false.
To prove security, we introduce a new technique for analyzing polynomials over multilinear map encodings. This technique shows that the types of encodings an adversary can create are much more restricted than was previously known, and is a crucial step toward achieving postzeroizing security. We also believe the technique is of independent interest, as it yields efficiency improvements for existing schemes.Category / Keywords: Obfuscation, zeroizing attacks, evasive functions Date: received 26 Feb 2015, last revised 14 Jul 2015 Contact author: enmiles at cs ucla edu Available format(s): PDF | BibTeX Citation Version: 20150714:211409 (All versions of this report) Short URL: ia.cr/2015/167 Discussion forum: Show discussion | Start new discussion