@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.
this is probably over my head...but isn't that basically the same as solving a block? or not because solving a block is an approximation and for the KDIM we would need the exact key?
You guys need to do some more study on SHA-256.
To break a completely random 2^256 with the biggest computer networks we have currently would literally take more time than the life of the universe.