Quote from: mvdheuvel1983 on March 24, 2014, 02:03:19 PM

I'm trying to understand why cryptocurrency private keys are safe. Maybe it's a n00b question, but here I go.

I understand that if you know someone's private key, this is means you can transfer the coins. I tried this with my CGA wallet, I used dumpprivkey to get my private key, deleted my wallet file, restarted the client, and all I needed to to to get my balance back was entering "importprivkey ". You don't need anything else than the private key.

What if someone ran a powerful computer which runs a program that does nothing else than:

1) generate random key
2) importprivkey
3) return to 1

Wouldn't that mean that this program could randomly pick up users balances, like some lottery?

I don't know if I'm off topic, but I read somewhere (can't remember the article) that approximately the number of possible private keys is similar to the numer of atoms in the universe, and running a computer capable of cracking a private key would require the energy produced by a star...obviously there is always luck, but seems unlikely