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