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	<theartlav@gmail.com>
Date: Wed, 24 Jan 2018 06:50:10 +0300
Message-ID: <CAJRVQkBPQR3Gz3AtWFgK_Z_9vDVZvR4Ws=f+tUZ3Y0mdswuk_g@mail.gmail.com>
To: bitcoin-dev@lists.linuxfoundation.org
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Subject: [bitcoin-dev] Why is deriving public key from the signature not
	used in Segwit?
Precedence: list

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?