FROST: Flexible Round-Optimized Schnorr Threshold Signatures
draft-irtf-cfrg-frost-00

Document Type Active Internet-Draft (cfrg RG)
Authors Chelsea Komlo  , Ian Goldberg 
Last updated 2021-02-18 (latest revision 2021-02-08)
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CFRG                                                            C. Komlo
Internet-Draft                  University of Waterloo, Zcash Foundation
Intended status: Informational                               I. Goldberg
Expires: 12 August 2021                           University of Waterloo
                                                         8 February 2021

      FROST: Flexible Round-Optimized Schnorr Threshold Signatures
                        draft-irtf-cfrg-frost-00

Abstract

   In this draft, we present FROST, a Flexible Round-Optimized Schnorr
   Threshold signature scheme that reduces network overhead during
   signing operations while protecting against forgery attacks
   applicable to prior similar threshold and multisignature
   constructions.

   FROST can be safely used without limiting concurrency of signing
   operations yet allows for true threshold signing, as only a threshold
   number of participants are required for signing operations.  Here, we
   define FROST as a two-round protocol, but it can be optimized to a
   single-round single-round signing protocol as the first round can be
   performed as a batched pre-processing stage.

Discussion Venues

   This note is to be removed before publishing as an RFC.

   Discussion of this document takes place on the FROST Working Group
   mailing list (frost@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/frost/.

   Source for this draft and an issue tracker can be found at
   https://github.com/chelseakomlo/frost-spec.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on 12 August 2021.

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction
   2.  Change Log
   3.  Terminology
   4.  Security Considerations
   5.  Basic Assumptions
     5.1.  Selection of participants
     5.2.  Communication channels
     5.3.  Protocol Failures
   6.  Notation
   7.  Cryptographic Dependencies
   8.  Protocol Overview
   9.  FROST Key Generation
   10. FROST Signing
   11. References
     11.1.  Normative References
     11.2.  Informative References
   Acknowledgments
   Authors' Addresses

1.  Introduction

   DISCLAIMER: This is a work-in-progress draft of FROST.

   RFC EDITOR: PLEASE REMOVE THE FOLLOWING PARAGRAPH The source for this
   draft is maintained in GitHub.  Suggested changes should be submitted
   as pull requests at https://github.com/chelseakomlo/frost-spec.
   Instructions are on that page as well.

   In this draft, we present FROST, a Flexible Round-Optimized Schnorr
   Threshold signature scheme.  FROST reduces network overhead during
   signing operations by optimizing for efficiency over robustness.
   FROST uses a novel technique to allow for fully parallelized use
   while protecting against forgery attacks that are applicable to prior
   similar threshold and multisignature constructions.

   FROST achieves its efficiency improvements in part by allowing the
   signing protocol to abort in the presence of a misbehaving
   participant (who can be identified and excluded from future signing
   operations).

2.  Change Log

   draft-00

   *  Submitted a basic draft after adoption of draft-komlo-frost as a
      working group item.

3.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

4.  Security Considerations

   In this draft, we specify key generation using a trusted dealer.

5.  Basic Assumptions

   We maintain assumptions about how participants are selected as well
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