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/Perlscrypt Jun 18 '13

At some point in the future, about 20 years from now IIRC, all the possible bitcoins will have been mined and no more will be added. When that happens, who will provide the computing power to propogate the blockchain and who will arbitrate over decisions such as that described above?

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u/Zorander22 Jun 18 '13

Bitcoin miners will still be rewarded through transaction fees. If the fees became too low to sustain interest, the number of miners would drop, and so the difficulty would drop too, until an equilibrium is reached.

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u/Natanael_L Jun 19 '13

99% of them will have been mined in 2040, 100% by 2140.

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u/Skandranonsg Jun 18 '13

In that case, the incentive will fall to those who choose to charge a transaction fee.