Date: Wed, 10 Jun 2020 23:34:53 +0000
To: Antoine Riard <antoine.riard@gmail.com>
From: ZmnSCPxj <ZmnSCPxj@protonmail.com>
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Cc: Gleb Naumenko <naumenko.gs@gmail.com>,
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Time-dilation Attacks on the Lightning Network
Precedence: list

Good morning Antoine and Gleb,

One thing I have been idly thinking about would be to have a *separate* sof=
tware daemon that performs de-eclipsing for your Bitcoin fullnode.

For example, you could run this deeclipser on the same hardware as your Bit=
coin fullnode, and have the deeclipser bind to port 8334.
Then you set your Bitcoin fullnode with `addnode=3Dlocalhost:8334` in your =
`bitcoind.conf`.

Your Bitcoin fullnode would then connect to the deeclipser using normal P2P=
 protocol.

The deeclipser would periodically, every five minutes or so, check the late=
st headers known by your fullnode, via the P2P protocol connection your ful=
lnode makes.
Then it would attempt to discover any blocks with greater blockheight.

The reason why we have a separate deeclipser process is so that the deeclip=
ser can use a plugin system, and isolate the plugins from the main fullnode=
 software.
For example, the deeclipser could query a number of plugins:

* One plugin could just try connecting to some random node, in the hopes of=
 getting a new connection that is not eclipsed.
* Another plugin could try polling known blockchain explorers and using the=
ir APIs over HTTPS, possibly over Tor as well.
* Another plugin could try connecting to known Electrum servers.
* New plugins can be developed for new mitigations, such as sending headers=
 over DNS or blocks over mesh or etc.

Then if any plugin discovers a block later than that known by your fullnode=
, the deeclipser can send an unsolicited `block` or `header` message to you=
r fullnode to update it.

The advantage of using a plugin system is that it becomes easier to prototy=
pe, deploy, and maybe even test new de-eclipsing mitigations.

At the same time, by running a separate daemon from the fullnode, we provid=
e some amount of process isolation in case some problem with the plugin sys=
tem exists.
The deeclipser could be run by a completely different user, for example, an=
d you might even run multiple deeclipser daemons in the same hardware, with=
 different non-overlapping plugins, so that an exploit of one plugin will o=
nly bring down one deeclipser, with other deeclipser daemons remaining func=
tional and still protecting your fullnode.

Finally, by using the P2P protocol, the fullnode you run could be a non-Bit=
coin-Core fullnode, such as btcd or rust-bitcoin or whatever other fullnode=
 implementations exist, assuming you actually want to use them for some rea=
son.

What do you think?

Regards,
ZmnSCPxj