Subject: I-D Action: draft-ford-cfrg-cosi-00.txt

From: [email-masked]
Date: Fri, 30 Jun 2017 12:00:39 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories.

        Title           : Collective Edwards-Curve Digital Signature Algorithm
        Authors         : Bryan Ford
                          Nicolas Gailly
                          Linus Gasser
                          Philipp Jovanovic
	Filename        : draft-ford-cfrg-cosi-00.txt
	Pages           : 15
	Date            : 2017-06-30

Abstract:
   Collective signatures are compact cryptographic proofs showing that
   several distinct secret key holders, called cosigners, have
   cooperated to sign a given message.  This document describes a
   collective signature extension to the EdDSA signing schemes for the
   Ed25519 and Ed448 elliptic curves.  A collective EdDSA signature
   consists of a point R, a scalar s, and a bitmask Z indicating the
   specific subset of a known group of cosigners that produced this
   signature.  A collective signature produced by n cosigners is of size
   64+ceil(n/8) bytes for Ed25519 and 114+ceil(n/8) bytes for Ed448,
   respectively, instead of 64n and 114n bytes for n individual
   signatures.  Further, collective signature verification requires only
   one double scalar multiplication rather than n.  The verifier learns
   exactly which subset of the cosigners participated, enabling the
   verifier to implement flexible acceptance-threshold policies, and
   preserving transparency and accountability in the event a bad message
   is collectively signed.

The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ford-cfrg-cosi/

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