@sdrebel -- on HT you wrote "i believe a fair comparison would be that faking a dkim signature is as easy as solving a btc block. it can happen, but it takes a shitload of computing power to do it"

Nope, that's not right, if by solving a block you mean a miner generating a new block.

It's more like faking a DKIM signature is like finding the private key for an already-generated address, i.e., being able to spend someone else's bitcoins without knowing their private key. Bitcoin is secure because that's so *extremely* computationally difficult. Much harder than generating a candidate block for the blockchain.