How realistic(practical) this attack is ?
Very doable if you can afford to spend 10/15 millions of $
Any rich guy could happily do it without problems...
But due to Sathoshi's genius clever design, would-be-attackers are instead incentivised to use their resources as legit miners instead, thus increasing the strength of the main block chain.
Sorry, I'm confusing, because I'm a newbie in Bitcoins world, just two weeks of knowledge about it...
Until today, I believed that miners only do mining... What they do more? Why miners are so important to keep the safety of the Bitcoins network?
If miners cash-out someday, this will leave the network unprotected.. But why?!?
By the way, then it is possible spend the same Bitcoin twice?! Since I have enough computing power for this?
And then it is also possible reverse the payment?!
All depends on the computational power?!
If the U.S. government and Fed tries to do these things today?! We are fucked?!
I'm very curious and concerned!
Thanks!
Thiago