Watermarking Cryptographic Capabilities
Name
18m1164834.pdf
Description
Published version
Size
620 KB
Format
Adobe PDF
Checksum (MD5)
8e0e185b8cd6e616ce52db5617667ca4
Author(s)
Cohen, Aloni(Aloni Jonathan)
Holmgren, Justin Lee
Nishimaki, Ryo
Vaikuntanathan, Vinod
Wichs, Daniel
Date Issued
December 2018
Journal
SIAM Journal on Computing
Publisher
Society for Industrial & Applied Mathematics (SIAM)
Citation
Cohen, Aloni et al., "Watermarking Cryptographic Capabilities." SIAM Journal on Computing 47, 6 (December 2018): 2157–2202 doi. 10.1137/18M1164834 ©2018 Authors
Version
Final published version
Abstract
A watermarking scheme for programs embeds some information called a mark into a program while preserving its functionality. No adversary can remove the mark without damaging the functionality of the program. In this work, we study the problem of watermarking various cryptographic programs such as pseudorandom function (PRF) evaluation, decryption, and signing. For example, given a PRF F, we create a marked program C that evaluates F(·). An adversary that gets C cannot come up with any program C ∗ in which the mark is removed but which still evaluates the PRF correctly on even a small fraction of the inputs. The work of Barak et al. [CRYPTO 2001, Springer, Berlin, 2001, pp. 1-18; J. ACM, 59 (2012), 6] shows that, assuming indistinguishability obfuscation (iO), such watermarking is impossible if the marked program C evaluates the original program with perfect correctness. In this work we show that, assuming iO, such watermarking is possible if the marked program C is allowed to err with even a negligible probability, which would be undetectable to the user. We also significantly extend the impossibility results to our relaxed setting. Our watermarking schemes are public key, meaning that we use a secret marking key to embed marks in programs, and a public detection key that allows anyone to detect marks in programs. Our schemes are secure against chosen program attacks where the adversary is given oracle access to the marking functionality. We emphasize that our security notion of watermark nonremovability considers arbitrary adversarial strategies to modify the marked program, in contrast to the prior works. ©2018 Society for Industrial and Applied Mathematics
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
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DOI of Published Version
https://doi.org/10.1137/18M1164834
