Can private keys be exported more than once in Electrum client so long as the've not been spent?

Assuming one exported the private keys from one's offline Electrum wallet to a CSV file (also offline), they obviously have not been 'spent'. The whole thing was done offline. My question is this: if I were now to go online and try to spend the bitcoins covered by those private keys, are the bitcoins still there? Or does the exportation of the private keys to the CSV file equal the spending of those coins so far as the Electrum client is concerned? To put it another way, can the private keys be exported more than once so long as they have not been spent? I'm hope I'm explaining myself clearly.

[I recently made my first Bitcoin purchase and I did so into an Electrum wallet, which I am currently keeping on an offline computer. I could not see my private keys anywhere and was unsure that I'd received them and so I exported them to the CSV file purely to ascertain that I had, in fact, received them. (I would not do so on any future purchases, now that I'm confident that the private keys would be there to be generated from the seed since they are plainly more secure unexported from an encrypted wallet than on a CSV file, but, hey, my first time and no evidence or explanation that I indeed had received them ...] - Terrylei

terrylei

Posted 2013-06-07T02:05:25.000

Reputation: 83

Answers

It seems like you don't understand how Bitcoins, private keys and bitcoin addresses work, so I'll make it simple:

As I explained to you here https://bitcoin.stackexchange.com/a/11479/2467 , you should not (more like MUST NOT) export your private keys from an Electrum seed. This can compromise all your private keys.

Your private keys are derived from your seed every time you make a payment to sign the transaction. So there's no need to see them, the client calculate them for you, use them, and hide them again. all you need is to keep your seed safe.

If you want to know the balance in your offline Electrum wallet's addresses you can use a seedless wallet on an online computer. To do that look for your Master Public Key in the offline Electrum, and restore from your MPK on an online computer.

You don't need your private keys to know the balance on their public addresses anyway. Public addresses are public and if you have already received on them, you can check their balance on Blockchain.info

rdymac

Posted 2013-06-07T02:05:25.000

Reputation: 1 357

Thanks for your patience, Rdymac. I heard your message that I should NOT have exported the pr. Keys, but had already done so at that point. Now that I HAVE exported (but not spent) them, can I still spend them from the same wallet? Sorry if I seem obtuse. My guess is that I can still spend them from the wallet and no harm done, except that I’ve unnecessarily compromised their security. Is this correct? Or does the wallet spit them out once only? If so, how can I use them in their current form (CSV file)? Yes, blockchain.info confirms the balance of my coins. – terrylei – 2013-06-07T10:45:21.463

@terrylei when you export you privkeys from Electrum (and almost any other client) it is just a copy. That means that two copies of you privkeys exist, so it is easier to find them. On Electrum it is particularly dangerous because your privkeys are generated deterministically, so if someone have a few of your privkeys, he can presumably calculate all your subsequent privkeys you'll ever use. Spend the coins you have to a new Electrum seed and use that one. – rdymac – 2013-06-08T14:09:17.373

This eplanation addresses what was really concerning me ... that what was exported was only copies. However, I really appreciate your advice about the need to spend the coins to a new Electrum seed and why this is necessary. I will do as you suggest. Thanks again. I need to check out and understand what a deterministic wallet is and how it works. I'm not at all tech savvy, so it's quite a learning curve. Many thanks for your attention to my problem. -Terrylei – terrylei – 2013-06-10T01:55:43.893

I'm not sure this was made clear but also you do not "Receive" public keys. when you generate a new wallet your client generates public and private keys. Using math you can get your public keys from your private keys but not the other way around (eg. you can not determin your private key from your public keys). With your private key you can now sign transactions to be broadcast the Bitcoin network and anyone can use your public keys to verify that YOU authorized the transactions.

What people are saying here about the need to NOT export your keys is because normally Electrum encrypts that data. making it hard for someone else to use should they gain access to your computer (ether physically or remotely). By exporting your private keys to a csv file you've just done the difficult work for any would be attacker.

Brandon

Posted 2013-06-07T02:05:25.000

Reputation: 1