Paper 2014/231

Self-Updatable Encryption with Short Public Parameters and Its Extensions

Kwangsu Lee

Abstract

Cloud storage is very popular since it has many advantages, but there is a new threat to cloud storage that was not considered before. {\it Self-updatable encryption} that updates a past ciphertext to a future ciphertext by using a public key is a new cryptographic primitive introduced by Lee, Choi, Lee, Park, and Yung (Asiacrypt 2013) to defeat this threat such that an adversary who obtained a past-time private key can still decrypt a (previously unread) past-time ciphertext stored in cloud storage. Additionally, an SUE scheme can be combined with an attribute-based encryption (ABE) scheme to construct a powerful revocable-storage ABE (RS-ABE) scheme introduced by Sahai, Seyalioglu, and Waters (Crypto 2012) that provides the key revocation and ciphertext updating functionality for cloud storage. In this paper, we propose an efficient SUE scheme and its extended schemes. First, we propose an SUE scheme with short public parameters in prime-order bilinear groups and prove its security under a $q$-type assumption. Next, we extend our SUE scheme to a time-interval SUE (TI-SUE) scheme that supports a time interval in ciphertexts. Our TI-SUE scheme has short public parameters and also secure under the $q$-type assumption. Finally, we propose the first large universe RS-ABE scheme with short public parameters in prime-order bilinear groups and prove its security in the selective revocation list model under a $q$-type assumption.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Published elsewhere. Designs, Codes and Cryptography
DOI
10.1007/s10623-015-0039-9
Keywords
Public-key encryptionSelf-updatable encryptionCiphertext delegationCloud storageBilinear maps
Contact author(s)
guspin @ korea ac kr
History
2015-01-25: last of 2 revisions
2014-04-01: received
See all versions
Short URL
https://ia.cr/2014/231
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2014/231,
      author = {Kwangsu Lee},
      title = {Self-Updatable Encryption with Short Public Parameters and Its Extensions},
      howpublished = {Cryptology ePrint Archive, Paper 2014/231},
      year = {2014},
      doi = {10.1007/s10623-015-0039-9},
      note = {\url{https://eprint.iacr.org/2014/231}},
      url = {https://eprint.iacr.org/2014/231}
}
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