Verifiable Random Functions (VRFs)
draft-goldbe-vrf-00
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Network Working Group S. Goldberg
Internet-Draft Boston University
Intended status: Standards Track D. Papadopoulos
Expires: September 14, 2017 University of Maryland
J. Vcelak
NS1
March 13, 2017
Verifiable Random Functions (VRFs)
draft-goldbe-vrf-00
Abstract
A Verifiable Random Function (VRF) is the public-key version of a
keyed cryptographic hash. Only the holder of the private key can
compute the hash, but anyone with public key can verify the
correctness of the hash. VRFs are useful for preventing enumeration
of hash-based data structures. This document specifies several VRF
constructions that are secure in the cryptographic random oracle
model. One VRF uses RSA and the other VRF uses Eliptic Curves (EC).
Status of This Memo
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This Internet-Draft will expire on September 14, 2017.
Copyright Notice
Copyright (c) 2017 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
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
Goldberg, et al. Expires September 14, 2017 [Page 1]
Internet-Draft VRF March 2017
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Rationale . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 3
1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. VRF Algorithms . . . . . . . . . . . . . . . . . . . . . . . 3
3. VRF Security Properties . . . . . . . . . . . . . . . . . . . 4
3.1. Full Uniqueness or Trusted Uniqueness . . . . . . . . . . 4
3.2. Full Pseudorandomness or Selective Pseudorandomness . . . 5
3.3. Full Collison Resistance or Trusted Collision Resistance 5
4. RSA Full Domain Hash VRF (RSA-FDH-VRF) . . . . . . . . . . . 6
4.1. RSA-FDH-VRF Proving . . . . . . . . . . . . . . . . . . . 7
4.2. RSA-FDH-VRF Proof To Hash . . . . . . . . . . . . . . . . 7
4.3. RSA-FDH-VRF Verifying . . . . . . . . . . . . . . . . . . 8
5. Elliptic Curve VRF (EC-VRF) . . . . . . . . . . . . . . . . . 8
5.1. EC-VRF Proving . . . . . . . . . . . . . . . . . . . . . 10
5.2. EC-VRF Proof To Hash . . . . . . . . . . . . . . . . . . 10
5.3. EC-VRF Verifying . . . . . . . . . . . . . . . . . . . . 11
5.4. EC-VRF Auxiliary Functions . . . . . . . . . . . . . . . 11
5.4.1. EC-VRF Hash To Curve . . . . . . . . . . . . . . . . 11
5.4.2. EC-VRF Hash Points . . . . . . . . . . . . . . . . . 13
5.4.3. EC-VRF Decode Proof . . . . . . . . . . . . . . . . . 13
5.5. EC-VRF Ciphersuites . . . . . . . . . . . . . . . . . . . 14
6. Implementation Status . . . . . . . . . . . . . . . . . . . . 15
7. Security Considerations . . . . . . . . . . . . . . . . . . . 15
7.1. Key Generation . . . . . . . . . . . . . . . . . . . . . 15
7.2. Proper randomness for EC-VRF . . . . . . . . . . . . . . 16
7.3. Timing attacks . . . . . . . . . . . . . . . . . . . . . 16
7.4. Selective vs Full Pseudorandomness . . . . . . . . . . . 16
8. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 17
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 17
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