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From: vjudeu@gazeta.pl
To: "bitcoin-dev@lists.linuxfoundation.org"
 <bitcoin-dev@lists.linuxfoundation.org>
Date: Fri, 04 Mar 2022 21:46:04 +0100
Message-Id: <158234619-439597ed4ddc4a9f90ea573513b5f5a3@pmq4v.m5r2.onet>
Subject: [bitcoin-dev] One testnet to rule them all
Precedence: list

In testnet3, anyone can become a miner, it is possible to even mine a block=
 on some CPU, because the difficulty can drop to one. In signet, we create =
some challenge, for example 1-of-2 multisig, that can restrict who can mine=
, so that chain can be "unreliably reliable". Then, my question is: why sig=
nets are introducing new coins out of thin air, instead of forming two-way =
peg-in between testnet3 and signet?

The lack of coins is not a bug, it is a feature. We have more halvings in t=
estnet3 than in mainnet or signets, but it can be good, we can use this to =
see, what can happen with a chain after many halvings. Also, in testnet3 th=
ere is no need to have any coins if we are mining. Miners can create, move =
and destroy zero satoshis. They can also extend the precision of the coins,=
 so a single coin in testnet3 can be represented as a thousand of coins in =
some signet sidechain.

Recently, there are some discussions regarding sidechains. Before they will=
 become a real thing, running on mainnet, they should be tested. Nowadays, =
a popular way of testing new features is creating a new signet with new rul=
es. But the question still remains: why we need new coins, created out of t=
hin air? And even when some signet wants to do that, then why it is not peg=
ged into testnet3? Then it would have as much chainwork protection as testn=
et3!

It seems that testnet3 is good enough to represent the main chain during si=
dechain testing. It is permissionless and open, anyone can start mining sid=
echain blocks, anyone with a CPU can be lucky and find a block with the min=
imal difficulty. Also, because of blockstorms and regular chain reorgs, som=
e extreme scenarios, like stealing all coins from some sidechain, can be te=
sted in a public way, because that "unfriendly and unstable" environment ca=
n be used to test stronger attacks than in a typical chain.

Putting that proposal into practice can be simple and require just creating=
 one Taproot address per signet in testnet3. Then, it is possible to create=
 one testnet transaction (every three months) that would move coins to and =
from testnet3, so the same coins could travel between many signets. New sig=
nets can be pegged in with 1:1 ratio, existing signets can be transformed i=
nto signet sidechains (the signet miners rule that chains, so they can enfo=
rce any transition rules they need).