Paper 2018/273

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

Prabhanjan Ananth, Xiong Fan, and Elaine Shi


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.

Available format(s)
Public-key cryptography
Publication info
Published by the IACR in ASIACRYPT 2019
attribute-based encryptionRAMsLWE
Contact author(s)
xfan @ cs cornell edu
2020-08-04: last of 3 revisions
2018-03-22: received
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Creative Commons Attribution


      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},
      note = {\url{}},
      url = {}
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