Subject: Re: [bitcoin-dev] Drivechain -- Request for Discussion

From: Paul Sztorc <[email-masked]>
Date: Mon, 22 May 2017 22:00:19 +0200

On May 22, 2017 3:13 PM, "Tier Nolan via bitcoin-dev" <bitcoin-dev@lists.
linuxfoundation.org> wrote:

On Mon, May 22, 2017 at 5:19 PM, Paul Sztorc via bitcoin-dev <
[email-masked]> wrote:

>
> In the future, when there is no block subsidy, a rich attacker can also do
> that in mainchain Bitcoin.
>

I don't think they are the same.

With Bitcoin, you only get to reverse recent transactions.  If you actually
reversed 2-3 weeks of transactions, then the Bitcoin price would fall,
destroying the value of the additional coins you managed to obtain.  Even
if their was no price fall, you can only get a fraction of the total.

I would replace "Bitcoins you manage to steal" with "Bitcoins you manage to
double-spend". Then, it still seems the same to me.

With BMM, you can "buy" the entire reserve of the sidechain by paying
(timeout) * (average tx fees).  If you destroy a side-chain's value, then
that doesn't affect the value of the bitcoins you manage to steal.

It may destroy great value if it shakes confidence in the sidechain
infrastructure. Thus, the value of the stolen BTC may decrease, in addition
to the lost future tx fee revenues of the attacked chain.

http://www.truthcoin.info/blog/drivechain/#drivechains-security

In my view, sidechains should only exist at all if they positively impact
Bitcoin's value. It is therefore desirable for miners to steal from chains
that provide no value-add.

> In point of fact, the transactions *are* validated...by sidechain full
> nodes, same as Bitcoin proper.
>
>
The big difference is that Bitcoin holds no assets on another chain.  A
side-chain's value is directly linked to the fact that it has 100% reserves
on the Bitcoin main chain.  That can be targeted for theft.

Again, I don't really think it is that different. One could interchange
"recent txns" (those which could be double-spent within 2-3 weeks) with
"sidechain deposit tnxs".