Paper 2017/709
spKEX: An optimized lattice-based key exchange
Sauvik Bhattacharya, Oscar Garcia-Morchon, Ronald Rietman, and Ludo Tolhuizen
Abstract
The advent of large-scale quantum computers has resulted in significant interest in quantum-safe cryptographic primitives. Lattice-based cryptography is one of the most attractive post-quantum cryptographic families due to its well-understood security, efficient operation and versatility. However, LWE-based schemes are still relatively bulky and slow. In this work, we present spKEX, a forward-secret, post-quantum, unauthenticated lattice-based key-exchange scheme that combines four techniques to optimize performance. spKEX relies on Learning with Rounding (LWR) to reduce bandwidth; it uses sparse and ternary secrets to speed up computations and reduce failure probability; it applies an improved key reconciliation scheme to reduce bandwidth and failure probability; and computes the public matrix A by means of a permutation to improve performance while allowing for a fresh A in each key exchange. For a quantum security level of 128 bits, our scheme requires 30% lesser bandwidth than the LWE-based key-exchange proposal Frodo [9] and allows for a fast implementation of the key exchange.
Note: Section on hybrid attack has been added. As a result, the proposed parameters have been altered.
Metadata
- Available format(s)
-
PDF
- Publication info
- Preprint. MINOR revision.
- Keywords
- lattice techniqueskey exchange
- Contact author(s)
- ludo tolhuizen @ philips com
- History
- 2017-08-17: revised
- 2017-07-25: received
- See all versions
- Short URL
- https://ia.cr/2017/709
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2017/709,
author = {Sauvik Bhattacharya and Oscar Garcia-Morchon and Ronald Rietman and Ludo Tolhuizen},
title = {{spKEX}: An optimized lattice-based key exchange},
howpublished = {Cryptology {ePrint} Archive, Paper 2017/709},
year = {2017},
url = {https://eprint.iacr.org/2017/709}
}
