Cryptology ePrint Archive: Report 2017/766

GLYPH: A New Insantiation of the GLP Digital Signature Scheme

Arjun Chopra

Abstract: In 2012 Guneysu, et al. proposed GLP, a practical and efficient post-quantum digital signature scheme based on the computational hardness of the Ring Learning With Errors problem. It has some advantages over more recent efficient post-quantum digital signature proposals such as BLISS and Ring-TESLA, but Ring Learning With Errors hardness is more fully understood now than when GLP was published a half decade ago. Although not broken, GLP as originally proposed is no longer considered to offer strong levels of security.

We propose GLYPH, a new instantiation of GLP, parametrised for 128 bits of security under the very conservative assumptions proposed in [2], which gives a strong assurance that it will be secure against forgery even if there are further developments in lattice cryptanalysis. Parameters to obtain this strong security level in an efficient manner were not possible within the original formulation of GLP, as they are not compatible with a signature compression algorithm, and to address this we also propose a new form of the compression algorithm which works efficiently with wider ranges of parameters.

We have produced a software implementation of GLYPH, and we place it in the public domain at

Category / Keywords: public-key cryptography / Cryptography, Post-Quantum Cryptography, Lattice, Ring-LWE, Ring Learning With Errors, Digital Signature, GLP

Date: received 8 Aug 2017, last revised 14 Aug 2017

Contact author: arjun chopra vsc at safe-mail net

Available format(s): PDF | BibTeX Citation

Note: This new version includes a link to our software implementation.

Version: 20170814:160420 (All versions of this report)

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