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 \SKf (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},
      url = {https://eprint.iacr.org/2016/524}
}
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