Cassascius vs Quantum computing

[pk1978]

Hi guys,

Sorry, if its not the best place to post this.

Basically,  I have a few Cas coins and recently got concerned if we are in any risk Quantum might cracks the wallets.
Alternatively, if btc network goes through a Quantum upgrade, we might be forced to peel all of the coins.

Of course I would love to see a solution where we can keep it unpeeled

Thanks much for any pointers /info.
Links to educate myself.

[_act_]

If it is true that quantum computers will take just 9 minutes to steal bitcoin from unconfirmed transactions, this can make some people to open the coins and send the bitcoin to a safe address that has been newly created from bitcoin upgrade against quantum computers.

But Cassascius coins are collectibles, new ones can created.

[bestcoin_59]

Hello,

I'm not an expert, but i came across this excellent article, which explains the real threats:
https://fr.tradingview.com/news/cointribune:91fc5a278b858:0/
For those who don't understand the French, basically the vulnerable addresses are the ones
for which the PUBLIC key has been exposed. It can happen if and only if
1) You used a P2PK address (very unlikely if the wallet is created after 2011)
OR
2) You sent BTC with that address and you don't use a change address,
that is a separate address with a new UTXO. Nowdays, softwares like
Electrum use new addresses for each transactions.

There is also a tool where you can check the vulnerability of a particular address:
https://www.projecteleven.com/bitcoin-risq-list

As said above, i'm not an expert, so please feel free to contradict me if you think
i'm wrong. I hope it helps nevertheless.

[gpfrag]

Genuine questions here so forgive me if they sound trite

1) aren’t all public addrrsses available via blockchain?  This includes ballet ‘virgin’ bitcoin such as the recent .00325 slabs they were selling.
2) How do we know that the website you provided isn’t compiling addresses once we ‘check’. 

[bestcoin_59]

Genuine questions here so forgive me if they sound trite

1) aren’t all public addrrsses available via blockchain?  This includes ballet ‘virgin’ bitcoin such as the recent .00325 slabs they were selling.

I think you are confusing the address and the public key. It is possible to compute the address from the public key via hash functions, but quantum computing can't derive the public key from the address.

The threat of quantum computing, is that, these computers might be able to derive the PRIVATE key from the PUBLIC key, via shor's algorithm.

2) How do we know that the website you provided isn’t compiling addresses once we ‘check’. 

In fact, the website already list all the vulnerable addresses. It is something public.

I final note though, if after entering an address, you see something:
0 BTC compromised

I think that it does NOT mean that this address is safe. It is just that the balance is displayed as an integer...
Therefore you may have something like 0.7 BTC unsafe...

Hope it helps 

[bestcoin_59]

So to sum up regarding casacious coins. I checked some random addresses taken from:
http://casascius.uberbills.com/
and they don't seem to fall in the P2PK category. Therefore, if unpeeled, these coins should
be safe.

Fell free to elaborate if you think i'm wrong.

[OgNasty]

The current danger of quantum computing being warned about comes from transactions submitted and waiting in the mempool. It is likely a quantum fix will be put in place to address that danger. So as long as you update to the latest Bitcoin software prior to submitting a transaction to move funds from a Casascius coin, you should be fine. At least for another decade.

[pk1978]

Ok, so we are good for the time being.

But, second issue, if btc is forced to do a hard fork to make the chain Quantum safe.

That would eventually mean, or could mean, that these coins are left behind?
Or forced to be peeled.

[BookofNick]

Ok, so we are good for the time being.

But, second issue, if btc is forced to do a hard fork to make the chain Quantum safe.

That would eventually mean, or could mean, that these coins are left behind?
Or forced to be peeled.

A fork hopefully doesn't mean coins are "left behind" in any way. That kind of fork (with rules to make old coins unspendable) would be highly unlikely to have any kind of success.

Likely, the coins would continue to be spendable on both of the new chains, as was the case with the BTC / BCH fork. Since Casascius coins were created and loaded "pre fork," their face value (i.e. a 1 BTC) would be spendable on both potential chains.

Should quantum attacks become real and not just hypothetical (as it currently is just a hypothetical), and there emerges a real danger against Cas coins, they should be peeled and moved.

All that being said, unpeeled Cas coins are low to no risk for quantum attack as the attack vectors are currently predicted / projected because of the reasons explained in posts above.

[OgNasty]

It appears there is already a fix in place to allow for safe transactions without a fork even when quantum computers are a reality. Good news for all Casascius or any other cold storage Bitcoin holders.

https://github.com/avihu28/Quantum-Safe-Bitcoin-Transactions