Paper 2020/893

Toward an Asymmetric White-Box Proposal

Lucas Barthelemy

Abstract

This article presents a proposal for an asymmetric white-box scheme. While symmetric white-box is a well studied topic (in particular for AES white-box) with a rich literature, there is almost no public article on the topic of asymmetric white-box. However, asymmetric white-box designs are used in practice by the industry and are a real challenge. Proprietary implementations can be found in the wild but are usually heavily obfuscated and their design is not public, which makes their study impractical. The lack of public research on that topic makes it hard to assess the security of those implementations and can cause serious security issues. Our main contribution is to bring a public proposal for an asymmetric white-box scheme. Our proposal is a lattice-based cryptographic scheme that combines classical white-box techniques and arithmetic techniques to offer resilience to the white-box context. In addition, thanks to some homomorphic properties of our scheme, we use homomorphic encoding techniques to increase the security of our proposal in a white-box setting. The resulting scheme successfully performs a decryption function without exposing its secret key while its weight remains under 20 MB. While some of our techniques are designed around specific characteristics of our proposal, some of them may be adapted to other asymmetric cryptosystems. Moreover, those techniques can be used and improved in a less restrictive model than the white-box one: the grey-box model. This proposal aims to raise awareness from the research community on the study of asymmetric white-box cryptography.

Metadata
Available format(s)
PDF
Category
Implementation
Publication info
Preprint. MINOR revision.
Keywords
white-box cryptographyasymmetric white-box cryptographylattice based cryptographysoftware protectionhomomorphic cryptography
Contact author(s)
lucas barthelemy92 @ gmail com
History
2020-07-17: revised
2020-07-16: received
See all versions
Short URL
https://ia.cr/2020/893
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2020/893,
      author = {Lucas Barthelemy},
      title = {Toward an Asymmetric White-Box Proposal},
      howpublished = {Cryptology ePrint Archive, Paper 2020/893},
      year = {2020},
      note = {\url{https://eprint.iacr.org/2020/893}},
      url = {https://eprint.iacr.org/2020/893}
}
Note: In order to protect the privacy of readers, eprint.iacr.org does not use cookies or embedded third party content.