whoa! i guess if Peter Todd said it, it must be true!
look, i like Peter for the most part, but his specialty is stirring the pot.
Every one of his statements is true.
It isn't that the split of hash across pools is fake, it is that there is absolutely no way to know, and the incentive to lie is both there and has increased.
It's quite silly to pretend this isn't a concern. The security model of mining is based on any actor's share being small. Small doesn't mean <=50% or even <20%, its more like 2% or maybe 0.2%.
you're certainly welcome to be concerned. i'm not. Nash's Equilibrium, whom we just happen to be talking about, looks to me to have distributed the hash rate nicely since the ghash incident according to the game theory. and probably for the last time as the hash rate technological advances have plateaued. this was expected as hardware is now becoming commoditized and comparably powered units can affordably get into the hands of smaller miners again. they still have to associate with a pool, of course, but those pools are being diversified and spread quite obviously.
any attack by a gvt has also been discussed quite a bit. there are thing that can be done by the network to block the source according to Gavin:
http://gavintech.blogspot.nl/2012/05/neutralizing-51-attack.htmlIf a 51% attacker stopped including all broadcast transactions in blocks "we" would quickly figure out a rule or rules to reject their blocks.
Something like "ignore a longer chain orphaning the current best chain if the sum(priorities of transactions included in new chain) is much less than sum(priorities of transactions in the part of the current best chain that would be orphaned)" would mean a 51% attacker would have to have both lots of hashing power AND lots of old, high-priority bitcoins to keep up a transaction-denial-of-service attack. And they'd pretty quickly run out of old, high-priority bitcoins and would be forced to either include other people's transactions or have their chain rejected.
I'm tempted to code that up and run some tests on a testnet-in-a-box, but there are much higher priority things on my TODO list; I don't think a 51% attack is likely. You'd spend a lot of time and money on an attack that "we" would neuter within a day or two.
there are lots of ppl monitoring the BC for just such an attack. and for what? double spend for a cup of coffee? i don't think so.