Towards Attribute-Based Encryption for RAMs from LWE: Sub-linear Decryption, and More

Prabhanjan Ananth; Xiong Fan; Elaine Shi

Paper 2018/273

Towards Attribute-Based Encryption for RAMs from LWE: Sub-linear Decryption, and More

Prabhanjan Ananth, Xiong Fan, and Elaine Shi

Abstract

Attribute based encryption (ABE) is an advanced encryption system with a built-in mechanism to generate keys associated with functions which in turn provide restricted access to encrypted data. Most of the known candidates of attribute based encryption model the functions as circuits. This results in significant efficiency bottlenecks, especially in the setting where the function associated with the ABE key is represented by a random access machine (RAM) and a database, with the runtime of the RAM program being sublinear in the database size. In this work we study the notion of attribute based encryption for random access machines (RAMs), introduced in the work of Goldwasser, Kalai, Popa, Vaikuntanathan and Zeldovich (Crypto 2013). We present a construction of attribute based encryption for RAMs satisfying sublinear decryption complexity assuming learning with errors; this is the first construction based on standard assumptions. Previously, Goldwasser et al. achieved this result based on non-falsifiable knowledge assumptions. We also consider a dual notion of ABE for RAMs, where the database is in the ciphertext and we show how to achieve this dual notion, albeit with large attribute keys, also based on learning with errors.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Published by the IACR in ASIACRYPT 2019
Keywords: attribute-based encryption RAMs LWE
Contact author(s): xfan @ cs cornell edu
History: 2020-08-04: last of 3 revisions; 2018-03-22: received; See all versions
Short URL: https://ia.cr/2018/273
License: CC BY

BibTeX

@misc{cryptoeprint:2018/273,
      author = {Prabhanjan Ananth and Xiong Fan and Elaine Shi},
      title = {Towards Attribute-Based Encryption for {RAMs} from {LWE}: Sub-linear Decryption, and More},
      howpublished = {Cryptology {ePrint} Archive, Paper 2018/273},
      year = {2018},
      url = {https://eprint.iacr.org/2018/273}
}