how do you delete posts???

the security of the system is based on the difficulty, and thus the resources required to produce the next genuine block. you'd have to have more than 50% of the total mining capacity of the network in order to pass off a fake next block.

it's more that after funding a company that has developed advanced technology on taxpayers' dime, selling it for pennies on the dollar to the chinese doesn't seem like a very smart idea. then again, if they have any technology that's all that great, why wouldn't ford, gm, or someone else purchase them. or even honda…

if you were that motivated to screw with the data the pilots were using, you could also modify their paper charts and swap them out... there is no perfect solution, and no uncrackable safe.