Paper 2016/524

Single-Key to Multi-Key Functional Encryption with Polynomial Loss

Sanjam Garg and Akshayaram Srinivasan

Abstract

Functional encryption (FE) enables fine-grained access to encrypted data. In a FE scheme, the holder of a secret key $\SK_f$ (associated with a function $f$) and a ciphertext $c$ (encrypting plaintext $x$) can learn $f(x)$ but nothing more. An important parameter in the security model for FE is the number of secret keys that adversary has access to. In this work, we give a transformation from a FE scheme for which the adversary gets access to a single secret key (with ciphertext size sub-linear in the circuit for which this secret key is issued) to one that is secure even if adversary gets access to an {unbounded} number of secret keys. A novel feature of our transformation is that its security proof incurs only a {\em polynomial} loss.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
A minor revision of an IACR publication in TCC 2016
Keywords
Functional EncryptionIND-based securitygeneric transforms
Contact author(s)
akshayaram @ berkeley edu
History
2016-08-23: last of 2 revisions
2016-05-29: received
See all versions
Short URL
https://ia.cr/2016/524
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2016/524,
      author = {Sanjam Garg and Akshayaram Srinivasan},
      title = {Single-Key to Multi-Key Functional Encryption with Polynomial Loss},
      howpublished = {Cryptology ePrint Archive, Paper 2016/524},
      year = {2016},
      note = {\url{https://eprint.iacr.org/2016/524}},
      url = {https://eprint.iacr.org/2016/524}
}
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