Bitcoin Forum

Back when BTC was young, I know I had an old wallet on an old computer and didn't backup/save anything. The BTC payouts were much larger years ago and I'm sure this scenario happened to people with "large" BTC wallets.

Just curious...  ::)

They are lost. Forever...

Or at least until someone breaks double sha256.

I wouldn't hold my breath  :P

That's disappointing... There should be a way to "somehow" gain access to idle wallets. Reward the miners somehow... Maybe once all bitcoins are... "mined".

There have been many discussions of this and they all end with the issue of people having cold storage wallets and cold coins. Go check the dev section of these forums -> https://bitcointalk.org/index.php?board=6.0

Right, how do you know it's a lost wallet versus a wallet in cold storage. I'd like to know what the current $ value of all lost coins is...huge.  ;)

Quantum computers might crack it some day.

When our colonies on Mars rebel and overthrow us, they can come here and "crack" our old wallets and use the BTC. It'd be like a reverse stealing of the gold from the New World back in the day. Sort of.

ECDSA is what allows spending. SHA256^2 prevents double spending.

-bgc

Now that would make for some juicy story additions to a good sci-fi movie.

Ah true.

I actually meant to say breaks sha256 and ripemd-160. An attacker could maybe reverse a key from an address then, right?  I also should have put a ;) because I highly doubt this will happen.

i would hunt down that hard drive and hope i could recover the wallet (or at least some private keys)

I came here to say this too, there seem to be a lot of posts that are more "newbie-related" seeping out of the Newbie forum for some reason in the last couple months.

I'm curious if SHA256 collisions would allow us to potentially recover lost coins (or steal them...)?

I understand it is infeasible with current computing power, but quantum computing promises to effectively half the keylength.

The point is that if with quantum computing you're able to recover so called lost coins, you're also able to steal ALL coins.
There's simply no difference between lost and non-lost coins, any lost coin recovery attemp would be the end of Bitcoin as a whole.

aye, the one thing bitcoin has going for it there is that we are able to bump the new priv keys up to 512bit, 1024bit, etc etc. This would require anyone with coins still sitting in an old 256bit addy to move them to a new one to get that security though.

Yeah, that would be possible, it would also require anyone who owns physical bitcoins (e.g. Cascasius) to destroy and re-digitalize them.
There will probably be millions of coins stolen in the meantime, what would make todays thefts look like peanuts.
But at least the system might survive.  :D

The lost bitcoins would be sitting in addresses which would not have been "upgraded".

It might be possible we take advantage of this vulnerability to recover "lost" bitcoins. If ASICs in the future are in the range of $/TH and the block reward is low enough, it might make sense for miners to attempt to "crack" these vulnerable addresses and release the stagnant coins instead of mining new coins.

You would hope if the old address, even if cold storage had real owners any more they would be still keeping up on Bitcoins and if smart would not only move their cold storage BTC to a new regular addy periodicly to help avoid that but would surely get their ass in gear to move to new 512bit addy asap if it was implemented because of the potential for new tech to greatly reduce the collision time.