Re: [Cfrg] draft-goldbe-vrf: Verifiable Random Functions

"Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu> Sun, 23 July 2017 02:26 UTC

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From: "Blumenthal, Uri - 0553 - MITLL" <uri@ll.mit.edu>
To: Tony Arcieri <bascule@gmail.com>, "cfrg@irtf.org" <cfrg@irtf.org>
Thread-Topic: [Cfrg] draft-goldbe-vrf: Verifiable Random Functions
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Date: Sun, 23 Jul 2017 02:25:54 +0000
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Subject: Re: [Cfrg] draft-goldbe-vrf: Verifiable Random Functions
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And I would *really* love it if we could have something like Elligator for more curves, such as the NIST-defined...

Regards,
Uri

Sent from my iPhone

> On Jul 22, 2017, at 12:09, Tony Arcieri <bascule@gmail.com> wrote:
> 
>> On Fri, Jul 21, 2017 at 9:32 AM, Dan Brown <danibrown@blackberry.com> wrote:
>> Answering myself below: VRFs have been around since 1999, so are not so new.  ‎Still don't like the name, and still have trouble seeing the value.
> 
> VRFs provide deterministic precommitments you can reveal at a later time. This is useful if you want to maintain a 1:1 mapping of low entropy inputs (e.g. names, email addresses, phone numbers) to some random values you can commit to in advance, e.g. through a timestamping service/transparency log.
> 
> Using a VRF means you can make these random outputs effectively public without them being subject to a preimage attack (so long as the VRF private key is not leaked). This way a key transparency server can prove a given user's keys were included in a transparency log without enabling spammers to obtain all of the names in the directory.
> 
> -- 
> Tony Arcieri
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