Verifiable Oblivious Pseudo-Random Functions with Public Metadata
draft-iyengar-cfrg-voprfmetadata-00

Document Type Active Internet-Draft (individual)
Authors Subodh Iyengar  , Ananth Raghunathan 
Last updated 2021-02-22
Stream (None)
Intended RFC status (None)
Formats plain text html xml pdf htmlized (tools) htmlized bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
cfrg                                                          S. Iyengar
Internet-Draft                                            A. Raghunathan
Intended status: Informational                                  Facebook
Expires: 26 August 2021                                 22 February 2021

   Verifiable Oblivious Pseudo-Random Functions with Public Metadata
                  draft-iyengar-cfrg-voprfmetadata-00

Abstract

   This document describes a verifable mechansim to bind public metadata
   to an existing Verifiable oblivious Pseduo-Random function
   [I-D.irtf-cfrg-voprf] (VOPRF).  Using zero knowledge proofs a
   receiver can verify that, for an input x, a VOPRF(k, x, metadata), is
   generated from a secret key k, as well as the given metadata.

Discussion Venues

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

   Discussion of this document takes place on the Crypto Forum Research
   Group mailing list (cfrg@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/search/?email_list=cfrg.

   Source for this draft and an issue tracker can be found at
   https://github.com/siyengar/verifiable-attribute-based-key-
   derivation.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 26 August 2021.

Iyengar & Raghunathan    Expires 26 August 2021                 [Page 1]
Internet-Draft             TODO - Abbreviation             February 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
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Simplified BSD License text
   as described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements  . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Preliminaries . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Prime-Order Group Dependency  . . . . . . . . . . . . . .   4
     2.2.  Other Conventions . . . . . . . . . . . . . . . . . . . .   4
     2.3.  Discrete log proofs . . . . . . . . . . . . . . . . . . .   4
   3.  Protocol  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.2.  Pre-Setup . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.3.  Evaluate VOPRF  . . . . . . . . . . . . . . . . . . . . .   7
   4.  Application considerations  . . . . . . . . . . . . . . . . .   9
     4.1.  Metadata bits . . . . . . . . . . . . . . . . . . . . . .   9
     4.2.  Encoding metadata . . . . . . . . . . . . . . . . . . . .   9
   5.  Comparison with other approaches  . . . . . . . . . . . . . .   9
     5.1.  Pairings  . . . . . . . . . . . . . . . . . . . . . . . .   9
     5.2.  Partially oblivious PRF . . . . . . . . . . . . . . . . .   9
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
     6.1.  Cryptographic security  . . . . . . . . . . . . . . . . .  10
       6.1.1.  n-Diffie Hellman exponent assumption  . . . . . . . .  10
       6.1.2.  Selective security vs full security . . . . . . . . .  10
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

Iyengar & Raghunathan    Expires 26 August 2021                 [Page 2]
Internet-Draft             TODO - Abbreviation             February 2021

1.  Introduction

   A VOPRF allows a client and server to evaluate a psuedo-random
   function "F(k, x)", with secret key "k", and input "x" without the
Show full document text