MIME-Version: 1.0
From: Matthew Roberts <matthew@roberts.pm>
Date: Thu, 4 Aug 2016 04:16:20 +1000
Message-ID: <CAAEDBiGMGWLeC81vkojGwEqQTT1HQaE=a3z114u6=FXXM2DRtQ@mail.gmail.com>
To: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
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Subject: [bitcoin-dev] BIP clearing house addresses
Precedence: list

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In light of the recent hack: what does everyone think of the idea of
creating a new address type that has a reversal key and settlement layer
that can be used to revoke transactions?

You could specify so that transactions "sent" from these addresses must
receive N confirmations before they can't be revoked, after which the
transaction is "settled" and the coins become redeemable from their
destination output. A settlement phase would also mean that a transaction's
progress was publicly visible so transparent fraud prevention and auditing
would become possible by anyone.

The reason why I bring this up is existing OP codes and TX types don't seem
suitable for a secure clearing mechanism; Nlocktimed TXs won't work for
this since you can't know ahead of time when and where a withdrawal needs
to be made, plus there's still the potential for key mismanagement; Similar
problems with OP_CHECKLOCKTIMEVERIFY apply too =E2=80=93 unless you keep a =
private
key around on the server which would defeat the purpose. The main use case
here, would be specifically to improve centralized exchange security by
making it impossible for a hot wallet to be raided all at once.

Thoughts?

Some existing background:

http://hackingdistributed.com/2016/08/03/how-bitfinex-heist-could-have-been=
-avoided/
-- Proposed the basic idea for a time-based clearing house but using
blockchains directly, this is a much better idea than my own.

roberts.pm/timechain -- My original paper written in 2015 which proposed a
similar idea for secure wallet design but implemented using time-locked
ECDSA keys. Obviously a blockchain would work better for this.

Other -- if the idea has already been brought up by other people, I
apologize.

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<div dir=3D"ltr">
<p style=3D"margin-bottom:0in">In light of the recent hack: what does
everyone think of the idea of creating a new address type that has a
reversal key and settlement layer that can be used to revoke
transactions?</p>

<p style=3D"margin-bottom:0in">You could specify so that transactions &quot=
;sent&quot;
from these addresses must receive N confirmations before they can&#39;t be =
revoked, after which the
transaction is &quot;settled&quot; and the coins become redeemable from the=
ir destination output. A settlement
phase would also mean that a transaction&#39;s  progress was publicly
visible so transparent fraud prevention and auditing would become possible =
by anyone.<br></p>

<p style=3D"margin-bottom:0in">The reason why I bring this up is
existing OP codes and TX types don&#39;t seem suitable for a secure
clearing mechanism; Nlocktimed TXs won&#39;t work for this since you
can&#39;t know ahead of time when and where a withdrawal needs to be
made, plus there&#39;s still the potential for key mismanagement;
Similar problems with OP_CHECKLOCKTIMEVERIFY apply too =E2=80=93 unless you
keep a private key around on the server which would defeat the
purpose. The main use case here, would be specifically to improve centraliz=
ed exchange security by making it impossible for a hot wallet to be raided =
all at once.

</p><p style=3D"margin-bottom:0in">Thoughts?</p><p style=3D"margin-bottom:0=
in">Some existing background:</p><p style=3D"margin-bottom:0in"><a href=3D"=
http://hackingdistributed.com/2016/08/03/how-bitfinex-heist-could-have-been=
-avoided/">http://hackingdistributed.com/2016/08/03/how-bitfinex-heist-coul=
d-have-been-avoided/</a> -- Proposed the basic idea for a time-based cleari=
ng house but using blockchains directly, this is a much better idea than my=
 own.</p><p style=3D"margin-bottom:0in"><a href=3D"http://roberts.pm/timech=
ain">roberts.pm/timechain</a> -- My original paper written in 2015 which pr=
oposed a similar idea for secure wallet design but implemented using time-l=
ocked ECDSA keys. Obviously a blockchain would work better for this.<br></p=
><p style=3D"margin-bottom:0in">Other -- if the idea has already been broug=
ht up by other people, I apologize. <br></p><p style=3D"margin-bottom:0in">=
<br>
</p>
<p style=3D"margin-bottom:0in"><br>
</p>
</div>

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