Importing private keys to an offline system and offline transactions

[Numerous64]

Hey, im a total newbie and i dont wanna lose my money.

So this is what im trying to do: import the private keys from a casascius gold bar to an electrum wallet that is contained in a ninjastik USB. I tried to do that offline and i got an error that i cannot import it.

The first thing that bugs me is that the private key i found in my bar starts with an s, not with a 5. Shouldnt all bitcoin private keys start with the number 5, not a letter? Not to mention i could not clearly distinguish whether it was a capital S or a small letter. Not that an offline system would verify it in anyway....

So my first question is, whats with my private key? Did i miss something here?

My second question is, can i even import private keys offline? Ive heard that i should be able to do that, and do an unverified online transaction, bring that transaction via USB to my offline electrum and then sign the transaction, and then bring it back to my online computer and verify it and the transaction happens, and this is supposed to be a secure way of sending BTC around. And my third question is, how exactly do i do that? Ive watched these videos:

https://www.youtube.com/watch?v=WK4JmfMCDBg

https://www.youtube.com/watch?v=SBVyFRb6ZZc

Now what i did not learn here is how did he "fund" his online computer that does not have private keys to do the transaction, did he import the public key of a BTC address that has BTC in it but no private key or what?


As you can propably see im all but tech savy and i have a bad luck with computers, so i hope someone can give me the simplest explanation on how do i do all this.

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[1715295243]

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[jackbox]

Cassius private keys are in compressed private key format. They can start with letters. To import you need to create a new wallet and import the private key into a new wallet. Then that wallet can import other private keys but can never use an HD seed in that particular wallet. This is a new feature so people don't lose money by forgetting a seeded wallet had imported private keys.

[Numerous64]

Hmm, what is and HD seed?

So of course i created a new wallet with a seed, i mean thats the first thing that happens when you open electrum. So i dont try to import the private keys there but instead create a new wallet again? So the first wallet i made is not good? Or what?

[jackbox]

Hmm, what is and HD seed?

So of course i created a new wallet with a seed, i mean thats the first thing that happens when you open electrum. So i dont try to import the private keys there but instead create a new wallet again? So the first wallet i made is not good? Or what?

HD Seed is what Electrum uses. It is a "Heuristic Deterministic" wallet. Meaning the seed will create addresses in a specific order based on that secret seed.

Yes, you cannot use the wallet you created with a seed to import a private key. To import a private key it must be a wallet that was NOT CREATED with an HD seed. Create a new wallet, enter the name, select restore and then enter the private key from the gold bar. It will be a new wallet file which you should immediately backup. This wallet will allow you to enter more private keys.  It only contain addresses of private keys you entered into it. It will not be like a normal electrum wallet. You can copy and save a receive address from the the first HD wallet you created, then if the private key has funds on it you can send them to the HD wallet and load that wallet file again. Of course, save the seed somewhere safe. Once a private key like this has been entered all the funds should be moved to a new address and that address never used again.

[jackbox]

Do the following:

Backup seed and wallet file.
Copy and paste receive address of Electrum wallet into notepad and save it.
File>New>Enter name>Restore>Enter compressed private key>Next
See if any btc at address from private key.
Send funds from the gold bar to the address you saved in new Electrum wallet.
Load original file and then have btc in Electrum wallet.
Never use private key or associated address from gold bar again.

Enjoy your new found btc if you found some.

[Numerous64]

Ok, sounds somewhat simple (though to my experience, everything that should be simple somehow just gets complicated ). But there is just one thing: im afraid of malware so thats why i would prefer not to go online, and instead do the transaction offline. Am i too paranoid and should i just do it online? Or is it too complicated anyway?

And of course if i do it offline then there is no way to tell if the btc is there until the point it arrives to the original created HD seed wallet, so i wont know if ive entered the correct private key etc....

How should i back up the seed and wallet file? Isnt it fine if i just have the file on that USB?

[jackbox]

Ok, sounds somewhat simple (though to my experience, everything that should be simple somehow just gets complicated ). But there is just one thing: im afraid of malware so thats why i would prefer not to go online, and instead do the transaction offline. Am i too paranoid and should i just do it online? Or is it too complicated anyway?

And of course if i do it offline then there is no way to tell if the btc is there until the point it arrives to the original created HD seed wallet, so i wont know if ive entered the correct private key etc....

How should i back up the seed and wallet file? Isnt it fine if i just have the file on that USB?

Offline would be too complicated for a beginner as you would need to use a wallet such as Armory with an offline and online mode. If you have a reliable anti-virus scanner the chances of your computer being infected are not that great. If you are that paranoid buy a Trezor (see link below in my signature) before transferring the funds. Transfer them directly to a Trezor address so it would be a sweep into basically cold storage.

If you have a valid Cassius gold bar private key it would be worth 100 BTC. So I would sweep it directly into something safe like a Trezor hardware wallet. Or you can create an offline wallet and then send the funds there. Up to you how you wish to proceed.

[Numerous64]

Ok thanks

No no not a real goldbar, we are talking of just normal cold storage really. Its in a bar form. The only gold over here is the electronic kind, y no what i mean

Thanks again

[Numerous64]

Ok, so the ninjastik has electrum 1.8.1 and it doesent have the new/restore button there in the file section like this 1.9.7 version in Ubuntu does. What now?