Cryptology ePrint Archive: Report 2014/794

Efficient Identity-Based Encryption over NTRU Lattices

Léo Ducas and Vadim Lyubashevsky and Thomas Prest

Abstract: Efficient implementations of lattice-based cryptographic schemes have been limited to only the most basic primitives like encryption and digital signatures. The main reason for this limitation is that at the core of many advanced lattice primitives is a trapdoor sampling algorithm(Gentry, Peikert, Vaikuntanathan, STOC 2008) that produced outputs that were too long for practical applications. In this work, we show that using a particular distribution over NTRU lattices can make GPV-based schemes suitable for practice. More concretely, we present the first lattice-based IBE scheme with practical parameters - key and ciphertext sizes are between two and four kilobytes, and all encryption and decryption operations take approximately one millisecond on a moderately-powered laptop. As a by-product, we also obtain digital signature schemes which are shorter than the previously most-compact ones of Ducas, Durmus, Lepoint, and Lyubashevsky from Crypto 2013.

Category / Keywords: public-key cryptography / Lattice Cryptography, Identity-Based Encryption, Digital Signatures, NTRU

Original Publication (with minor differences): IACR-ASIACRYPT-2014

Date: received 4 Oct 2014

Contact author: thomas prest at ens fr

Available format(s): PDF | BibTeX Citation

Version: 20141010:042514 (All versions of this report)

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