Date: Wed, 30 Aug 2023 11:05:03 +0000
To: ryan@breen.xyz
From: ZmnSCPxj <ZmnSCPxj@protonmail.com>
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Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Sentinel Chains: A Novel Two-Way Peg
Precedence: list


Good morning Ryan,


> I appreciate your questions, ZmnSCPxj.
>=20
> I will answer your second question first: Mainchain nodes do not ever val=
idate sidechain blocks. Sidechain nodes watch Bitcoin for invalid withdrawa=
ls, and publish signed attestations to a public broadcast network (such as =
Nostr) that a transaction is making an invalid withdrawal. These sidechain =
nodes are the so-called sentinels.

Let me reiterate my question:

Suppose I trust some sidechain node that is publishing such an attestation.

Then the sidechain node is hacked or otherwise wishes to disrupt the networ=
k for its own purposes.
And it attests that a valid sidechain withdrawal is actually invalid.

What happens then?

To the point, suppose that the attestation private key is somehow leaked or=
 determined by a third party that has incentive to disrupt the mainchain ne=
twork.

And it seems to me that this can be used to force some number of nodes to f=
ork themselves off the network.

This is dangerous as nodes may be monitoring the blockchain for time-sensit=
ive events, such as Lightning Network theft attempts.

Making "fork off bad miners!" a regular occurrence seems dangerous to me.

Regards,
ZmnSCPxj