Paper 2015/113
Stream ciphers: A Practical Solution for Efficient Homomorphic-Ciphertext Compression
Anne Canteaut, Sergiu Carpov, Caroline Fontaine, Tancrède Lepoint, María Naya-Plasencia, Pascal Paillier, and Renaud Sirdey
Abstract
In typical applications of homomorphic encryption, the first step consists for Alice to encrypt some plaintext m under Bob’s public key pk and to send the ciphertext c = HE_pk(m) to some third-party evaluator Charlie. This paper specifically considers that first step, i.e. the problem of transmitting c as efficiently as possible from Alice to Charlie. As previously noted, a form of compression is achieved using hybrid encryption. Given a symmetric encryption scheme E, Alice picks a random key k and sends a much smaller ciphertext c′ = (HE_pk(k), E_k(m)) that Charlie decompresses homomorphically into the original c using a decryption circuit C_E^{−1}. In this paper, we revisit that paradigm in light of its concrete implementation constraints; in particular E is chosen to be an additive IV-based stream cipher. We investigate the performances offered in this context by Trivium, which belongs to the eSTREAM portfolio, and we also propose a variant with 128-bit security: Kreyvium. We show that Trivium, whose security has been firmly established for over a decade, and the new variant Kreyvium have an excellent performance.
Metadata
- Available format(s)
-
PDF
- Publication info
- Preprint. MINOR revision.
- Keywords
- Stream CiphersHomomorphic cryptographyCiphertext compressionTrivium
- Contact author(s)
- tancrede lepoint @ cryptoexperts com
- History
- 2015-11-29: last of 2 revisions
- 2015-02-24: received
- See all versions
- Short URL
- https://ia.cr/2015/113
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2015/113,
author = {Anne Canteaut and Sergiu Carpov and Caroline Fontaine and Tancrède Lepoint and María Naya-Plasencia and Pascal Paillier and Renaud Sirdey},
title = {Stream ciphers: A Practical Solution for Efficient Homomorphic-Ciphertext Compression},
howpublished = {Cryptology {ePrint} Archive, Paper 2015/113},
year = {2015},
url = {https://eprint.iacr.org/2015/113}
}