<div dir="ltr"><div>Hi Tomas, by no means are you late, rather you're early! I just started packaging it together mainly to get the ball rolling.</div><div><br></div><div>(this is the current link for anyone not aware:)<br></div><div><a href="https://github.com/markblundeberg/bitcoincash.org/blob/schnorr/spec/schnorr-spec.md" target="_blank">https://github.com/markblundeberg/bitcoincash.org/blob/schnorr/spec/schnorr-spec.md</a><br></div><div><br></div><div>You're
absolutely right about one thing with the specified approach -- "the
security of signing becomes as weak as the weakest algorithm".<br></div><div><br></div><div>An
alternative approach might be to override the first byte of public keys
(say, use 08 & 09 for compressed schnorr pubkeys) which would force
'schnorr addresses' to be distinct from 'ecdsa addresses' even if the
mathematical keypairs are identical. This would allow to still use
OP_CHECKSIG and so we would still have P2PKH addresses. If we were to
add a new opcode like OP_CHECKSCHNORRSIG, it would get ugly since we
would need a new cashaddr address version for the new opcode.<br></div><div><br></div><div>If
there are any worries about weaker security, such a pubkey prefix byte
alteration would be the way to go. In future, a change in the pubkey
prefix byte would also be a good approach if we decide to add an
algorithm that doesn't use secp256k1. So it could be simpler in the very
long term.</div><div><br></div><div>-Mark<br></div><br><div class="gmail_quote"><div dir="ltr">On Thu, 6 Dec 2018 at 03:17, Tomas <<a href="mailto:tomas@bitcrust.org">tomas@bitcrust.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
<div><div>Hi all,<br></div>
<div><br></div>
<div>Thanks Shammah, for opening the discussion on the mailing list. Much appreciated.<br></div>
<div><br></div>
<div>I have a question regarding the choice of algorithm selection mechanism for Schnorr. In the spec it is stated that the first byte of the signature serialization is 0x73 to mark the signature as using the Schnorr algorithm.<br></div>
<div><br></div>
<div>As better algorithms may arise in the future I wonder whether this mechanism is suitable for future extensions; specifically compared to adding an (optional) algorithm-number argument to the checksig family of OPcodes. <br></div>
<div><br></div>
<div>A flaw of putting the algorithm in the signature seems to be that the security of signing becomes as weak as the weakest algorithm. As such it seems more natural to use an argument; the choice of algorithm is clearly part of the OPeration.<br></div>
<div><br></div>
<div>Maybe I am late to the game, but I am wondering whether this has been taken into consideration?<br></div>
<div><br></div>
<div>Tomas van der Wansem<br></div>
<div><br></div>
<div><br></div>
<div>On Sat, Dec 1, 2018, at 17:10, Shammah Chancellor wrote:<br></div>
<blockquote type="cite"><div>Hello Gentlepeople,<br></div>
<div><br></div>
<div>In the spirit of enabling others to work, I'd like to get the draft specification for May MERGED into the <a href="http://Bitcoincash.org" target="_blank">Bitcoincash.org</a> repository. Please review the existing spec here: <a href="https://github.com/bitcoincashorg/bitcoincash.org/pull/179" target="_blank">https://github.com/bitcoincashorg/bitcoincash.org/pull/179</a><br></div>
<div><br></div>
<div>And either explicitly reject, or approve it. The hope is that it will get merged, and then further people can do pull requests on top of that to improve it before Jan 3rd.<br></div>
<div><br></div>
<div>If you're unable to start a review in Github for some reason, please let me know. However, I believe anyone is able to do it at this time.<br></div>
<div><br></div>
<div>Kind Regards,<br></div>
<div>Shammah Chancellor<br></div>
<div>Bitcoin-ABC<br></div>
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