Quote from: Kettenmonster on April 29, 2012, 04:21:03 PM

Who is we?

I meant the party which in the above scenario wants to defend Bitcoin against the mentioned attack.

Quote from: Kettenmonster on April 29, 2012, 04:21:03 PM

Of cause you can start several btc chains. But this weakens the system.
Each chain can be attacked individually, being smaller drowning it is much easier.

I do not know. Maybe it depends on the exact attack and defense modes and all the remaining assumptions we make on the attacks.

For example: Let us assume we have 100 different chains and a centralized attacker (let's say the Fed) owning 51% of the hash and attempting an attack where he never adds transactions to the chain. Initially, the chains are all exact copies. With 49% of the hash and with 100 different chains there is a non-negligible chance that the good guys might at least in 1 or 2 of these chains win the block earlier than the attacker. So - under these assumptions - I am not sure if this claim is correct. I would agree, if attack modes also comprise double spending attacks (but still, I do not know - for lack of an appropriate model).

AFAIK we do not have the proper abstract models in place yet to be able to calculate and derive all the answers...