From: Gregory Maxwell <greg@xiph•org>
To: "Артём Литвинович" <theartlav@gmail•com>,
"Bitcoin Protocol Discussion"
<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Why is deriving public key from the signature not used in Segwit?
Date: Wed, 24 Jan 2018 04:25:28 +0000 [thread overview]
Message-ID: <CAAS2fgQmKY5206-ko9ttV4K_4aPfoWh7Jrx=XYetXLeknU30iw@mail.gmail.com> (raw)
In-Reply-To: <CAJRVQkBPQR3Gz3AtWFgK_Z_9vDVZvR4Ws=f+tUZ3Y0mdswuk_g@mail.gmail.com>
On Wed, Jan 24, 2018 at 3:50 AM, Артём Литвинович via bitcoin-dev
<bitcoin-dev@lists•linuxfoundation.org> wrote:
> Greetings.
>
> I wanted to ask what was the rationale behind still having both public
> key and signature in Segwit witness?
>
> As is known for a while, the public key can be derived from the
> signature and a quadrant byte, a trick that is successfully used both
> in Bitcoin message signing algorithm and in Ethereum transaction
> signatures. The later in particular suggests that this is a perfectly
> functional and secure alternative.
> Leaving out the public key would have saved 33 bytes per signature,
> which is quite a lot.
>
> So, the question is - was there a good reason to do it the old way
> (security, performance, privacy, something else?), or was it something
> that haven't been thought of/considered at the time?
It is slow to verify, incompatible with batch validation, doesn't save
space if hashing isn't used, and is potentially patent encumbered.
next prev parent reply other threads:[~2018-01-24 4:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-24 3:50 Артём Литвинович
2018-01-24 4:25 ` Gregory Maxwell [this message]
2018-01-24 10:24 ` Aymeric Vitte
2018-01-24 10:31 ` Gregory Maxwell
2018-01-24 11:16 ` Aymeric Vitte
2018-01-24 11:35 ` Gregory Maxwell
2018-01-24 12:03 ` Aymeric Vitte
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