The Stellar Consensus Protocol (SCP)
draft-mazieres-dinrg-scp-04

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Network Working Group                                           N. Barry
Internet-Draft                            Stellar Development Foundation
Intended status: Experimental                                    G. Losa
Expires: December 31, 2018                                          UCLA
                                                             D. Mazieres
                                                     Stanford University
                                                              J. McCaleb
                                          Stellar Development Foundation
                                                                 S. Polu
                                                             Stripe Inc.
                                                           June 29, 2018

                  The Stellar Consensus Protocol (SCP)
                      draft-mazieres-dinrg-scp-04

Abstract

   SCP is an open Byzantine agreement protocol resistant to Sybil
   attacks.  It allows Internet infrastructure stakeholders to reach
   agreement on a series of values without unanimous agreement on what
   constitutes the set of important stakeholders.  A big differentiator
   from other Byzantine agreement protocols is that, in SCP, nodes
   determine the composition of quorums in a decentralized way: each
   node selects sets of nodes it considers large or important enough to
   speak for the whole network, and a quorum must contain such a set for
   each of its members.

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 December 31, 2018.

Barry, et al.           Expires December 31, 2018               [Page 1]
Internet-Draft                     scp                         June 2018

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  The Model . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Configuration . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Input and output  . . . . . . . . . . . . . . . . . . . .   4
   3.  Protocol  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Federated voting  . . . . . . . . . . . . . . . . . . . .   5
     3.2.  Basic types . . . . . . . . . . . . . . . . . . . . . . .   7
     3.3.  Quorum slices . . . . . . . . . . . . . . . . . . . . . .   8
     3.4.  Nominate message  . . . . . . . . . . . . . . . . . . . .  10
     3.5.  Ballots . . . . . . . . . . . . . . . . . . . . . . . . .  12
     3.6.  Prepare message . . . . . . . . . . . . . . . . . . . . .  13
     3.7.  Commit message  . . . . . . . . . . . . . . . . . . . . .  16
     3.8.  Externalize message . . . . . . . . . . . . . . . . . . .  18
     3.9.  Summary of phases . . . . . . . . . . . . . . . . . . . .  18
     3.10. Message envelopes . . . . . . . . . . . . . . . . . . . .  19
   4.  Security considerations . . . . . . . . . . . . . . . . . . .  20
   5.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  20
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  21
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  21
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  21
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  22

1.  Introduction

   Various aspects of Internet infrastructure depend on irreversible and
   transparent updates to data sets such as authenticated mappings [cite
   Li-Man-Watson draft].  Examples include public key certificates and
   revocations, transparency logs [RFC6962], preload lists for HSTS
   [RFC6797] and HPKP [RFC7469], and IP address delegation
   [I-D.paillisse-sidrops-blockchain].