If a 51% attack actually happens, could one lose thier bitcoins in cold storage?

[cuddaloreappu]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

what can a normal non technical user do to save himself from this danger?

[joshraban76]

Always expect the worst case scenario, so yes, it could happen.

Maybe you could wait to see how we are going to pass this issue, as it's for the first time ever to happen.

[ljudotina]

If 51% attack happens, noone will steal your BTC. They will just be worth 0$....so no...you can not protect em...noone can except miners turning away their mining machines away from ghash. I hope devs are watching this and planning how to stop this from happening again.

[madmat]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

what can a normal non technical user do to save himself from this danger?

As far as i understand, no one can take your bitcoins without the private keys. So you are safe with cold storage.

Why could happen is double spending.

[Melbustus]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

No!!

A 51% could theoretically allow the attacker to double-spend coins that *they* already have.

YOUR coins are safe. No one can sign transactions for your coins, unless you've given them your private keys.

[david123]

No, this cannot happen. Only he who has the private key can initiate transactions.
What *can* happen is that a past transaction gets reversed. E.g. if you put your coins
on your cold wallet just yesterday and there is someone with almost 100% hashing power
and seriously determined to do so, he could fork and orphane all blocks from this transaction on.
Then the coins will be there where they used to be before they ended up in your cold wallet.

I'd say this is a purely theoretical threat, though. If you are the only one who has the private key,
you are the only one who has control over your coins.

[Melbustus]

Always expect the worst case scenario, so yes, it could happen.

No! See my post above.

...as it's for the first time ever to happen.

Also no. Deepbit had around 50% a couple years ago. Miners switched pools. It passed.

[Beliathon]

Take a deep breath, your money is safer in crypto cold storage than anywhere else in this solar system.

[coinmaster222]

Always expect the worst case scenario, so yes, it could happen.

Maybe you could wait to see how we are going to pass this issue, as it's for the first time ever to happen.

Better to remain silent and be thought a fool than to speak out and remove all doubt.

You guys should have a look at the wiki. The information is out there for you to access. Coming here to ask won't help much.

[megashira1]

Why is it so hard to solve this issue?

[david123]

What issue? Nothing needs to be resolved here.. Everything is fine. We should be happy about this opportunity
to grab some cheap coins

[joshraban76]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

No!!

A 51% could theoretically allow the attacker to double-spend coins that *they* already have.

YOUR coins are safe. No one can sign transactions for your coins, unless you've given them your private keys.

Are you sure about this ?

[BitCoinDream]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

No!!

A 51% could theoretically allow the attacker to double-spend coins that *they* already have.

YOUR coins are safe. No one can sign transactions for your coins, unless you've given them your private keys.

Are you sure about this ?

Yep, unless they reverse the Tx from where u got your coins

[david123]

Are you sure about this ?

You just have to read how bitcoin works.. In order to initiate a new transaction, you need the
private key. Otherwise you cannot sign that transaction. Technically you could build on
blocks containing wrongly signed transactions if you own the majority of the hashing speed, but then
it's no longer Bitcoin but someones private coin^^

You can fork and thus reverse transactions without knowing a private key. This would be bad news
for someone of course, but it has nothing to do with collecting coins belonging to someone else.

[Robert Paulson]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

what can a normal non technical user do to save himself from this danger?

yes, in a worst case scenario a 51% attack can erase all transactions since the last checkpoint, unless you got your bitcoins before that then you will lose them.
nothing can be done against this except hoping that ghash.io will stop controlling most of the hashing power in the network.

[shorena]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

what can a normal non technical user do to save himself from this danger?

yes, in a worst case scenario a 51% attack can erase all transactions since the last checkpoint, unless you got your bitcoins before that then you will lose them.
nothing can be done against this except hoping that ghash.io will stop controlling most of the hashing power in the network.

Huh? When was the last checkpoint?

[Robert Paulson]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

what can a normal non technical user do to save himself from this danger?

yes, in a worst case scenario a 51% attack can erase all transactions since the last checkpoint, unless you got your bitcoins before that then you will lose them.
nothing can be done against this except hoping that ghash.io will stop controlling most of the hashing power in the network.

Huh? When was the last checkpoint?

the last checkpoint in the source code is of block #279000 (https://github.com/bitcoin/bitcoin/blob/master/src/checkpoints.cpp) which was mined on 7th of January 2014.
so any bitcoins anyone got after that date are in danger in a worst case scenario.

[dooglus]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

No!!

A 51% could theoretically allow the attacker to double-spend coins that *they* already have.

YOUR coins are safe. No one can sign transactions for your coins, unless you've given them your private keys.

Not strictly true.

If the attacker *ever* owned your coins in the past, they can start their attack from before they sold them and rewrite history from that point forward.  Then you never bought them and your cold wallet is empty.

[david123]

I doubt if this repository has much authority. If someone with say almost 100% hashing power would
initiate a fork building on a block mined back in 2013, I don't see how a reversed bitcoin from jan. 8 is safer than
a reversed one from Jan. 6...

[juju]

If a 51% attack actually happens, could one lose  bitcoins in cold storage or in hot wallet..

No!!

A 51% could theoretically allow the attacker to double-spend coins that *they* already have.

YOUR coins are safe. No one can sign transactions for your coins, unless you've given them your private keys.

Not strictly true.

If the attacker *ever* owned your coins in the past, they can start their attack from before they sold them and rewrite history from that point forward.  Then you never bought them and your cold wallet is empty.

So what your telling me is I need to divest and gamble all my coins away?