Re: [Cfrg] new draft specifying VRFs (verifiable random functions)

Richard Barnes <rlb@ipv.sx> Tue, 14 March 2017 21:11 UTC

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From: Richard Barnes <rlb@ipv.sx>
Date: Tue, 14 Mar 2017 17:11:28 -0400
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To: Sharon Goldberg <sharon.goldbe@gmail.com>
Cc: "cfrg@irtf.org" <cfrg@irtf.org>
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Subject: Re: [Cfrg] new draft specifying VRFs (verifiable random functions)
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Hey Sharon,

Thanks for writing this up.  One quick, probably trivial question: How do
these VRFs differ from signature schemes?  From the API point of view, they
seem very similar, if you view the proof as the signature value.

Thanks,
--Richard

On Mon, Mar 13, 2017 at 10:27 AM, Sharon Goldberg <sharon.goldbe@gmail.com>
wrote:

> Several of us have been working a draft specification for Verifiable
> Random Functions (VRFs). A VRF is the public-key version of a keyed
> cryptographic hash function.  Only the holder of the private VRF key can
> compute the hash, but anyone with the corresponding public key can verify
> the correctness of the hash.   This draft has one VRF based on RSA, and
> another based on elliptic curves.
>
>  https://datatracker.ietf.org/doc/draft-goldbe-vrf/
>
> Our team is using a VRF to prevent zone enumeration with NSEC5 for DNSSEC
> [1,2]. The Google Key Transparency project is using a similar VRF to
> prevent key enumeration [3,4]. Open Whisper systems has also specified a
> similar VRF [5].   We think VRFs will be useful for other applications as
> well, so we think it would be helpful to have a standard way to implement
> them.
>
> We've requested an agenda slot at SAAG to talk about VRFs.  The chairs
> have requested that we send out a note to CFRG ahead of time, so here it
> is. Hope to chat in person at IETF and/or on this list.
>
> Thanks,
>
> Sharon
> (with Dimitris Papadopoulos, Jan Vcelak, Leonid Reyzin, Shumon Huque,
> David C Lawrence)
>
> [1] https://datatracker.ietf.org/doc/draft-vcelak-nsec5/
> [2] https://gitlab.labs.nic.cz/knot/nsec5-crypto
> [3] https://security.googleblog.com/2017/01/security-through-
> transparency.html
> [4] https://github.com/google/keytransparency/blob/master/core/vrf/vrf.go
> [5] https://whispersystems.org/docs/specifications/xeddsa/
>
> ---
> Sharon Goldberg
> Associate Professor, Computer Science, Boston University
> Sloan Research Fellow
> http://www.cs.bu.edu/~goldbe
>
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