The hash power that the network currently has it would be impossible for any singular entity to gain control of 51%. Could have happened in the early days, but I don't think this is a viable threat any more.
well not really impossible, it's actually doable, the point is that no one will do it because they could harm themselves more than anything else
You are wrong in assumption that hash power would stay high forever.
unless the price drop too much, i do not see how this will change in the future
One single miner isn't likely too, but a pool can, as demonstrated by the few pools coming quite close to 51% in the past. The price may or may not drop, but what do you think will happen when block reward halving occurs? Mining right now is barely profitable, and for most, not profitable. How will that be effected by the reward going from 25 to 12.5BTC per block? How many miners will continue to mine at a near 50% LOSS just on the power costs; Unless the decreased supply coming to market from miners causes the price to double, you will surely see quite a significant drop in hashrate(with exception to new types of powerful hardware coming out, but as far as im aware theres nothing like that on the way).
At the present bitcoin doesn't have any defense against a single new miner with 51% overtaking the network.
That isn't necessary.
How could bitcoin defend against itself?
Every miner should sign the blocks that he solves with his own key. After a miner has created a lot of blocks
over month that get accepted by other miners, new blocks of the same miner deserve more trust than blocks
of new miners.
How do you defend against one established miner using this new voting power to attack?
Allow every client to make the choice to distrust a miner. If a miner attacks the network than the community
can decide to distrust the key of that miner.
That isn't necessary.
How could bitcoin defend against itself?
Every miner should sign the blocks that he solves with his own key. After a miner has created a lot of blocks
over month that get accepted by other miners, new blocks of the same miner deserve more trust than blocks
of new miners.
How do you defend against one established miner using this new voting power to attack?
Allow every client to make the choice to distrust a miner. If a miner attacks the network than the community
can decide to distrust the key of that miner.
Giving nodes a 'trust level' defeats the decentralized trustless architecture that is the glory of bitcoin.. It opens vectors to 51% and other attacks in addition to being a step backwards for what blockchain technology accomplishes. Only problems come to mind from this....
