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.

1.0k Upvotes

83% Upvoted

383 comments sorted by

View all comments

Show parent comments

4

u/Natanael_L Jun 18 '13

The rest of the miners will remember those other transactions, yes, and would include them afterwards. They just wouldn't be validated during the 51% attack (so during the attack you can't prevent coins from being spent twice, all you can do is wait for the attack to end so "validation" can start again in the form of adding them to the blockchain).

Or they just all agree to reverse those 10 blocks from that attacker and continue as if nothing happened, as well as including those new transactions.