Cryptology ePrint Archive: Report 2018/056

Post-Quantum Signcryption From Lattice-Based Signatures

François Gérard and Keno Merckx

Abstract: In data security, the main objectives one tries to achieve are privacy, data integrity and authentication. In a public-key setting, privacy is reached through asymmetric encryption and both data integrity and authentication through signature. Meeting all the security objectives for data exchange requires to use a concatenation of those primitives in an encrypt-then-sign or sign-then-encrypt fashion. Signcryption aims at providing all the security requirements in one single primitive at a lower cost than using encryption and signature together. Most existing signcryption schemes are using ElGamal-based or pairing-based techniques and thus rely on the decisional Diffie-Hellman assumption. With the current growth of a quantum threat, we seek for post-quantum counterparts to a vast majority of public-key primitives. In this work, we propose a signcryption scheme based on the GLP signature inspired from a construction of Malone-Lee. It comes in two flavors, one integrating the usual lattice-based key exchange into GLP and the other merging the signature scheme with a RLWE encryption, which is more efficient, but outputs a larger signcryptext. Using the same set of operations as in existing constructions, our scheme can be implemented efficiently on various platforms, reusing optimized pieces of software or hardware presented in previous works.

Category / Keywords: public-key cryptography / Post-quantum, Signcryption, Lattice, GLP, Signature, Key exchange, Key encapsulation

Date: received 11 Jan 2018

Contact author: fragerar at ulb ac be

Available format(s): PDF | BibTeX Citation

Version: 20180116:130258 (All versions of this report)

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