But here’s a question to ask: just because I can double spend doesn’t mean I should.
There’s a lot of real world consequences of double spending that we don’t consider when just discussing theory and math.
If the rest of the world ever realizes that a double spend attack was conducted on Bitcoin, the value would plummet instantaneously because there’s no longer any belief in the finality of transactions and the security of the network My own bitcoin would drop in value as well, and that means I’ll lose a lot of money.
In addition, all the specialized hardware I own would be useless as well, since the hardware can only mine Bitcoin.
If Bitcoin is worthless, then so is the hardware.
So what are some other options? Well, I can bribe miners.
If I don’t own the hardware or don’t want to spend that much capital on hardware that’s about to become useless with a successful attack, might as well bribe other miners to mine on my own withheld chain.
But what if I’m a hostile government, adversarial altcoin, large institution, or other enemy to the network with a large amount of capital? Well, then there’s a way for me to make up my money even after buying all that hardware.
What I can do is called a “Goldfinger” attack, named after the James Bond movie of the same name.
The point of this attack is to profit off the destruction of some assets.
In the James Bond movie, the villain tried to profit off the destruction of gold in Ft.
Knox.
With Bitcoin, I can short the currency, meaning to place a bet on its devaluation.
I can first place a bet that Bitcoin is going to go down in value, then I can launch the double spend attack to make my prediction go through.
At this point, double spending on someone is — interestingly enough — just a means to an end.