Proof of Stake...

Sean Lynch seanl at
Fri Feb 7 12:09:36 PST 2014

The different transactions change the block hash, though, so it's the same
problem for the attacker that you originally pointed out with
proof-of-work, no?

On Fri, Feb 7, 2014 at 12:06 PM, David Vorick <david.vorick at>wrote:

> The problem is that you have a bunch of your own coins, so you are mining
> the chains that have been announced, but you are also mining possible
> chains that involve you that you never announced.
> So if I never announce that I destroy 10 coin days, but I have 10 coin
> days to destroy, there is an alternate reality that I'm also mining, If I
> don't like the current chain, I can add my own coin days to a different
> fork in the past to make that fork now the heaviest fork. Then I announce
> it. Especially if I'm working with a bunch of other people, they can add
> their own coins and we can work together to make it the longest chain. If
> it becomes the longest chain, they get back any coins they destroyed in an
> alternate history.
> So basically, it's very cheap for a set of collaborating nodes to build a
> forest of alternate chains, and the longest can change anytime we
> collectively alter the history or add another fork somewhere to make it the
> new longest. It's relatively inexpensive to balance all these forks.
> So it works as long as the powerful individuals aren't mining multiple
> chain simultaneously. But what's to stop them? So it's ultimately not very
> secure once powerful groups start attacking the currency.
> On Fri, Feb 7, 2014 at 2:53 PM, Sean Lynch <seanl at> wrote:
>> AIUI there are multiple ways to implement proof-of-stake. A friend of
>> mine proposed treating the chain with the most coin days destroyed (along
>> with correct difficulties for the standard proof-of-work function) as the
>> "longest" one rather than only the most difficult chain. Does that not work?
>> On Fri, Feb 7, 2014 at 2:40 AM, Lodewijk andré de la porte <l at>wrote:
>>> Any functional complaint + it being illogical economically. Power to
>>> those that rule. Fantastic plan.
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