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Re: [Cfrg] CFRG feedback on signing with secp256k1 curve

Dan Brown <danibrown@blackberry.com> Wed, 13 June 2018 11:52 UTC

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From: Dan Brown <danibrown@blackberry.com>
To: Peter Gutmann <pgut001@cs.auckland.ac.nz>, Mike Jones <Michael.Jones=40microsoft.com@dmarc.ietf.org>, "cfrg@irtf.org" <cfrg@irtf.org>
Thread-Topic: [Cfrg] CFRG feedback on signing with secp256k1 curve
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Date: Wed, 13 Jun 2018 11:52:03 +0000
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Subject: Re: [Cfrg] CFRG feedback on signing with secp256k1 curve
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‎what about sha256, see below...
 
From: Peter Gutmann
Sent: Wednesday, June 13, 2018 4:46 AM
To: Mike Jones; cfrg@irtf.org
Subject: Re: [Cfrg] CFRG feedback on signing with secp256k1 curve

Mike Jones <Michael.Jones=40microsoft.com@dmarc.ietf.org> writes:

>because Blockchain is using secp256k1 and is under tremendous scrutiny, it’s
>my assumption that if major security flaws were known, people would be widely
>talking about them

It's worse than that: Because of Blockchain, secp256k1 is under tremendous
scrutiny, and anyone finding a weakness is highly motivated *not* to talk
about it. 

secp256k1 is the curve I'd least want to use because it's such a massive
target for highly-motivated attackers.

Peter.‎

_______________________________________________

So you must even less want to use SHA256 because Blockchain uses it for the sigs and the chaining and mining (proof of work). It’s also used in some other places, so it is a bit more massive target than secp256k1.

Dan

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