### High Performance Lattice-based CCA-secure Encryption

Rachid El Bansarkhani and Johannes Buchmann

##### Abstract

Lattice-based encryption schemes still suffer from a low message throughput per ciphertext. This is mainly due to the fact that the underlying schemes do not tap the full potentials of LWE. Many constructions still follow the one-time-pad approach considering LWE instances as random vectors added to a message, most often encoded bit vectors. Recently, at Financial Crypto 2015 El Bansarkhani et al. proposed a novel encryption scheme based on the A-LWE assumption (Augmented LWE), where data is embedded into the error term without changing its target distributions. By this novelty it is possible to encrypt much more data as compared to the traditional one-time-pad approach and it is even possible to combine both concepts. In this paper we revisit this approach and propose amongst others several algebraic techniques in order to significantly improve the message throughput per ciphertext. Furthermore, we give a thorough security analysis as well as an efficient implementation of the CCA1-secure encryption scheme instantiated with the most efficient trapdoor construction. In particular, we attest that it even outperforms the CPA-secure encryption scheme from Lindner and Peikert presented at CT-RSA 2011.

Available format(s)
Category
Public-key cryptography
Publication info
Preprint. MINOR revision.
Keywords
Lattice-Based CryptographyEncryption SchemeLattice-Based Assumptions
Contact author(s)
elbansarkhani @ cdc informatik tu-darmstadt de
History
Short URL
https://ia.cr/2015/042

CC BY

BibTeX

@misc{cryptoeprint:2015/042,
author = {Rachid El Bansarkhani and Johannes Buchmann},
title = {High Performance Lattice-based CCA-secure Encryption},
howpublished = {Cryptology ePrint Archive, Paper 2015/042},
year = {2015},
note = {\url{https://eprint.iacr.org/2015/042}},
url = {https://eprint.iacr.org/2015/042}
}

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