Paper 2018/1030

Registration-Based Encryption from Standard Assumptions

Sanjam Garg, Mohammad Hajiabadi, Mohammad Mahmoody, Ahmadreza Rahimi, and Sruthi Sekar

Abstract

The notion of Registration-Based Encryption (RBE) was recently introduced by Garg, Hajiabadi, Mahmoody, and Rahimi [TCC'18] with the goal of removing the private-key generator (PKG) from IBE. Specifically, RBE allows encrypting to identities using a (compact) master public key, like how IBE is used, with the benefit that the PKG is substituted with a weaker entity called "key curator" who has no knowledge of any secret keys. Here individuals generate their secret keys on their own and then publicly register their identities and their corresponding public keys to the key curator. Finally, individuals obtain "rare" decryption-key updates from the key curator as the population grows. In their work, they gave a construction of RBE schemes based on the combination of indistinguishability obfuscation and somewhere statistically binding hash functions. However, they left open the problem of constructing RBE schemes based on standard assumptions. In this work, we resolve the above problem and construct RBE schemes based on standard assumptions (e.g., CDH or LWE). Furthermore, we show a new application of RBE in a novel context. In particular, we show that anonymous variants of RBE (which we also construct under standard assumptions) can be used for realizing abstracts forms of anonymous messaging tasks in simple scenarios in which the parties communicate by writing messages on a shared board in a synchronized way.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint. MINOR revision.
Keywords
Registration-based encryptionIdentity-based encryptionGarblingAnonymity
Contact author(s)
sruthi sekar1 @ gmail com
sanjamg @ berkeley edu
mdhajiabadi @ berkeley edu
mohammad @ virginia edu
ahmadreza @ virginia edu
History
2018-10-26: received
Short URL
https://ia.cr/2018/1030
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2018/1030,
      author = {Sanjam Garg and Mohammad Hajiabadi and Mohammad Mahmoody and Ahmadreza Rahimi and Sruthi Sekar},
      title = {Registration-Based Encryption from Standard Assumptions},
      howpublished = {Cryptology ePrint Archive, Paper 2018/1030},
      year = {2018},
      note = {\url{https://eprint.iacr.org/2018/1030}},
      url = {https://eprint.iacr.org/2018/1030}
}
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