feathercoin 51% attack

[lebaron93]

Can someone explain the 51% attack on feathercoin this past summer?  I've read some online articles about it and I still don't completely understand what happened.  Something about someone or a group of people that owned at least 51% of the quantity of feathercoin was able to trick the blockchain and spook other owners into selling off... or something like this.

And is this manipulation problem a serious threat to other cryptocurrencies, or have they learned from this episode how to prevent against it from happening again?

Thanks.

[dE_logics]

That's why CPU mining is the answer and PoS does not save us. Any coin supporting PoS is bad for a cryptocurrency.

See the link in my signature.

[drmadison]

Basically Cryptocoins are secure, based on the idea that the majority of miners are honest. Because of that, they all have to agree on transactions, and whatever the majority believes to be true, is taken as the truth and propagated.

If you're able to, for example, put up 51% of the hash-rate for a given alt-coin (Bitcoin has so much hashrate it's nowhere near possible) you can basically all agree on whatever transactions you want, making whatever transactions they want be valid