Cryptology ePrint Archive: Report 2019/654

Compact linkable ring signatures and applications

Brandon Goodell and Sarang Noether and RandomRun

Abstract: We introduce an efficient linkable ring multisignature construction, compact linkable spontaneous anonymous group (CLSAG) signatures. These admit d-dimensional keys with a specified linking coordinate but do not have signature sizes directly proportional to d. Compared to existing constructions used for signer-ambiguous confidential transactions without trusted setup, CLSAG signatures are smaller and more efficient in terms of both proving and verification time. CLSAG signatures also satisfy some rigorous security definitions: unforgeability depends upon the k-OMDL hardness assumption, linkability depends on unforgeability as well as the collision resistance of key aggregation, and signer-ambiguity depends on the DDH assumption. We demonstrate an application for CLSAG signatures for use in transacting multiple assets over ring signature-based transaction protocols.

Category / Keywords: applications / ring signatures, digital signatures

Date: received 3 Jun 2019, last revised 24 Sep 2019

Contact author: surae at getmonero org,sarang@getmonero org

Available format(s): PDF | BibTeX Citation

Version: 20190924:130827 (All versions of this report)

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