Paper 2013/690 Original: eprint.iacr.org/2013/690 ↗
Obfuscation ==> (IND-CPA Security =/=> Circular Security)
Abstract
Circular security is an important notion for public-key encryption schemes and is needed by several cryptographic protocols. In circular security the adversary is given an extra ``hint'' consisting of a cycle of encryption of secret keys i.e., (E_{pk_1}(sk_2),..., E_{pk_n}(sk_1)). A natural question is whether every IND-CPA encryption scheme is also circular secure. It is trivial to see that this is not the case when n=1. In 2010 a separation for n=2 was shown by [ABBC10,GH10] under standard assumptions in bilinear groups. In this paper we finally settle the question showing that for every $n$ there exist an IND-CPA secure scheme which is not n-circular secure. Our result relies on the recent progress in program obfuscation.
Metadata
- Available format(s)
PDF- Category
- Foundations
- Publication info
- Preprint.
- History
- 2014-05-02: last updated
- 2013-10-24: published
- Short URL
- https://ia.cr/2013/690
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2013/690,
author = {Antonio Marcedone and Claudio Orlandi},
title = {Obfuscation ==> (IND-CPA Security =/=> Circular Security)},
howpublished = {Cryptology {ePrint} Archive, Paper 2013/690},
year = {2013},
url = {https://eprint.iacr.org/2013/690}
}