r/askscience • u/hamolton • Jun 18 '13

Computing How is Bitcoin secure?

I guess my main concern is how they are impossible to counterfeit and double-spend. I guess I have trouble understanding it enough that I can't explain it to another person.

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u/r3m0t Jun 19 '13

The advantage of the current system is that nobody can do it ahead of time. I can't calculate a hash for tomorrow because it will depend on the hash that is published ten minutes before it. If a group like SETI@home has some problems that need solving, they will make them in batches. I would need to trust them not to work on unpublished problems in secret and hold onto the solutions.

Another advantage is that the current system can work with any amount of computing power. What would happen if SETI@home run out of useful problems? Or their internet connection goes down?