Re:Bitcoin blockchain issue - Mt Gox Bitcoin deposits tempor...
by judofyr on Tuesday March 12, 2013 @04:55AM
(#5360860)
If they pushed for people upgrading to 0.8 then everyone not upgrading would have their own blockchain. By getting more than 50% of the users to use 0.7, the rest of the 0.8 clients will discover that everyone else uses the 0.7 chain and thus replay all of the transactions on that chain.
Upgrading: Those who doesn't upgrade end up with their own chain.
Downgrading: Those who doesn't downgrade will automatically use the other chain when it becomes dominant.
> But with two separate blockchains, wouldn't both be vulnerable?
It's only the chain that doesn't become the main chain that is vulnerable. Because they're pushing for 0.7 to be the main chain you don't have to worry about double spending there.
Re:Bitcoin blockchain issue - Mt Gox Bitcoin deposits tempor...
by swhitt on Tuesday March 12, 2013 @10:02AM
(#5361822)
The choice was made for backwards compatibility. People are still running version 0.3-0.7 of bitcoind and up to this point that was not a problem. If we decided the 0.8 fork was canonical we'd lose a big chunk of the userbase.
A second thing that I don't understand is why 0.8 people are vulnerable to double-spending attacks. It wasn't said that 0.7 was safe, but it was said that 0.8 was vulnerable. But with two separate blockchains, wouldn't both be vulnerable? Or at least 0.7 because they don't accept 0.8's blockchain?