Fully Adaptive Decentralized Multi-Authority ABE

Pratish Datta; Ilan Komargodski; Brent Waters

Paper 2022/1311

Fully Adaptive Decentralized Multi-Authority ABE

Pratish Datta

, NTT Research

Ilan Komargodski, Hebrew University of Jerusalem, NTT Research

Brent Waters, The University of Texas at Austin, NTT Research

Abstract

Decentralized multi-authority attribute-based encryption (𝖬𝖠-𝖠𝖡𝖤) is a distributed generalization of standard (ciphertext-policy) attribute-based encryption where there is no trusted central authority: any party can become an authority and issue private keys, and there is no requirement for any global coordination other than the creation of an initial set of common reference parameters. We present the first multi-authority attribute-based encryption schemes that are provably fully adaptively secure. Namely, our construction is secure against an attacker that may corrupt some of the authorities as well as perform key queries adaptively throughout the life-time of the system. Our main construction relies on a prime order bilinear group where the 𝑘-linear assumption holds as well as on a random oracle. Along the way, we present a conceptually simpler construction relying on a composite order bilinear group with standard subgroup decision assumptions as well as on a random oracle. Prior to this work, there was no construction that could resist adaptive corruptions of authorities, no matter the assumptions used. In fact, we point out that even standard complexity leveraging style arguments do not work in the multi-authority setting.

Note: This version contains some minor modifications over the last one. These modifications are made in response to the comments of the anonymous reviewers during the review process.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: A major revision of an IACR publication in EUROCRYPT 2023
Keywords: attribute-based encryption multi-authority fully adaptive security bilinear pairings
Contact author(s): pratish datta @ ntt-research com
ilank @ cs huji ac il
bwaters @ cs utexas edu
History: 2023-02-15: revised; 2022-10-03: received; See all versions
Short URL: https://ia.cr/2022/1311
License: CC BY

BibTeX

@misc{cryptoeprint:2022/1311,
      author = {Pratish Datta and Ilan Komargodski and Brent Waters},
      title = {Fully Adaptive Decentralized Multi-Authority ABE},
      howpublished = {Cryptology ePrint Archive, Paper 2022/1311},
      year = {2022},
      note = {\url{https://eprint.iacr.org/2022/1311}},
      url = {https://eprint.iacr.org/2022/1311}
}