Full blockchain airgap

[takuma sato]

I want to use a laptop that never connects to the internet to sign transactions but I never liked how it shows 0 BTC. Of course I know about running a node with a watch-only wallet, I just want to be able to see the BTC on the airgap laptop too.

Since I want to keep backups of the full blockchain, I figured okay, I already got the full blockchain on the online laptop, well what if I send the blockchain files every week or so into the airgap computer thought a safe medium like optical media? This way I would have 2 copies of the blockchain, plus I would see the BTC value on the offline laptop too which is nice. I just want to see it as a peace of mind and I want all the transactions properly ordered with date etc (this is not the case with watch-only wallet, where I had to also manually add all the labels)

Anyway, my question is, can I do this and use PSBT as usual? I've read other people do this too and it shouldn't be a problem, your only concern would be to not enter media that could contain malware to move the blockchain files, but this is so incredibly unlikely if done properly. I also sometime apply offline updates to the Linux offline laptop (there are ways to do this offline) so it would be the same careful approach. You can also boot from Tails and move the files that way so you are never using a compromised OS.

I accept the risks involved, which I think are minimal, and you have way better odds at ending up robbed if you use a hardware wallet as a company has now your dox plus you being an owner of a hardware wallet. Im just asking if there are any technical problems doing this, or the two laptop workflow is the same if you have the full blockchain on your offline node?

Btw, at what rate is the blockchain growing nowadays? This will determine how often I update my offline backup.

[LoyceV]

It sounds like you're going to compromise security for aesthetics. One way or another, this always adds risks, so I wouldn't do it.

[Yamane_Keto]

The main advantage of an air-gapped device is that it reduces your interaction with online environments. you ONLY need raw data signature form the other device, but currently, you need two laptops and additional storage space for both, which is more than the cost of buying a new Hardware wallet.

I think you forgot that you asked this question before.

Most people would have 2 laptops using linux with a distro of choice. The laptop that signs transactions (cold wallet) wouldn't even have wifi card, bluetooth or anything wireless installed. This laptop does not have an updated blockchain. If you use Bitcoin Core I asume you would just install Bitcoin Core, open it, and basically leave it as if it wast trying to synch, but since there is no internet, it never synchs, and you just generate PSBT file and put it on the other Bitcoin Core laptop that has a watch only wallet with a synched blockchain, then broadcast it into the network.

Thing is, I always thought he hot wallet laptop looks kinda "ugly" or offputing, it just looks like you have 0 funds, and its trying to synch, but since there is no internet, it's just there doing nothing.

[MarryWithBTC]

It sounds like you're going to compromise security for aesthetics. One way or another, this always adds risks, so I wouldn't do it.

Copying the full blockchain to an air-gapped device is actually not solving any problem in this set up, it will just add unnecessary complexity. He is going to compromise security for convenience of seeing BTC balance. A watch-only wallet can handle that need.

Since I want to keep backups of the full blockchain, I figured okay, I already got the full blockchain on the online laptop, well what if I send the blockchain files every week or so into the airgap computer thought a safe medium like optical media?

The main principle of air-gap device is to minimize data transfer. Copying data weekly goes against this principle.

To me, copying the entire blockchain regularly just to view balance is inefficient. It is like downloading the whole library just to check one page of a book.

[satscraper]

Btw, at what rate is the blockchain growing nowadays? This will determine how often I update my offline backup.

You asked google answered  

So the growth rate is around 0.2–0.3 GB per day. At that pace  1 TB SSD will become obsolete fairly soon  especially since you need to reserve about 20% of its capacity for overprovisioning to maintain good performance. My node runs on  2 TB SSD, and I keep the second 1 TB SSD as  backup.

[joniboini]

Can't believe 1 TB SSD won't be enough soon. It's such a bad time since pricing is rising too. Well, I guess most people have some spare storage/SSDs if they're serious about running a node.

Anyway, I agree with others. If your issue is just not being able to see your balance, there are other solutions that won't compromise security. Alternatively, accept it as the trade-off.

[Zaguru12]

Can't believe 1 TB SSD won't be enough soon. It's such a bad time since pricing is rising too. Well, I guess most people have some spare storage/SSDs if they're serious about running a node.

I think as time goes on some people might actually decides to stick to running of prune node instead of the full node just to save cost of buying disks for larger space.

Anyway, I agree with others. If your issue is just not being able to see your balance, there are other solutions that won't compromise security. Alternatively, accept it as the trade-off.

No matter how anybody puts it out there as long as there is an iota of doubt of the device been infected with malware, it stops been an airgapped device for me. The question OP asks is a bit off to me because how he not want to see his balance on a watch only wallet when he definitely must still use the wallet for creating and broadcasting of the transaction

[takuma sato]

The main advantage of an air-gapped device is that it reduces your interaction with online environments. you ONLY need raw data signature form the other device, but currently, you need two laptops and additional storage space for both, which is more than the cost of buying a new Hardware wallet.

I think you forgot that you asked this question before.

Most people would have 2 laptops using linux with a distro of choice. The laptop that signs transactions (cold wallet) wouldn't even have wifi card, bluetooth or anything wireless installed. This laptop does not have an updated blockchain. If you use Bitcoin Core I asume you would just install Bitcoin Core, open it, and basically leave it as if it wast trying to synch, but since there is no internet, it never synchs, and you just generate PSBT file and put it on the other Bitcoin Core laptop that has a watch only wallet with a synched blockchain, then broadcast it into the network.

Thing is, I always thought he hot wallet laptop looks kinda "ugly" or offputing, it just looks like you have 0 funds, and its trying to synch, but since there is no internet, it's just there doing nothing.

I accept the risks involved, which I think are minimal, and you have way better odds at ending up robbed if you use a hardware wallet as a company has now your dox plus you being an owner of a hardware wallet. The 2 laptop setup is way safer. Im just asking if there are any technical problems doing this. I assume it's exactly the same, you just have the convenience of seeing what is actually going on on your offline laptop without trusting the online node code is making it show things accurately.
Watch-only wallets are also annoying as I described because they do not have labels and transactions are not properly shown in order:

https://bitcointalk.org/index.php?topic=5576086.0

So please, do not lecture me in the risks of moving data into your offline laptop. I understand it, I just feel safer, psychologically even, if I see the actual BTC count, and the transactions properly labeled and in correct time order. When im making transactions im already moving data with the PSBT files anyway, and I rarely make transactions, so the window of opportunity of any attacks is near zero. There are way bigger chances that your Trezor phones home, or your Ledger purchase leaks in a data breach on their company and now you are at risk of 5$ wrench attacks etc. I would never use a hardware wallet because of that. On the other hand, here im dealing with open source code, with hardware I control that is not attached to a dox that says "you own a hardware wallet", and there is a near zero attack surface since any data is being moved offline, when rarely moved, with a layer of protection (two computers offline using Tails) or even optical media through fully encrypted devices. The peace of mind I would get from seeing that the funds are indeed there, are worth it for me, plus getting all the transactions in order, with all labels etc, without having to fully trust that the online node is showing things properly, and like I said, I barely make transactions these days, so I could just update the blockchain every x months when I want to make a transaction. I simply do not want to trust the PSBT thing is working as intended. All this descriptors stuff, there is so much new stuff on BTC compared to many years ago, I don't have the time to keep track of everything. I want to see my funds visible "as-is". Then I can work from there. Remember that sometimes software mistakes happen. Like we just saw some bug that deleted wallets during migration. The less things I have to trust the best. So I want the funds shown on the same device, with the full blockchain, and I can then make transactions from a place where I feel confident everything is ok, and not be paranoid about missing change addresses, using the wrong address because it's not labeled properly or in the wrong chronological order etc. The only conclusion I have found is that this is the best thing to do. Specially if you have an old wallet from 10+years.

Btw, at what rate is the blockchain growing nowadays? This will determine how often I update my offline backup.

You asked google answered  

So the growth rate is around 0.2–0.3 GB per day. At that pace  1 TB SSD will become obsolete fairly soon  especially since you need to reserve about 20% of its capacity for overprovisioning to maintain good performance. My node runs on  2 TB SSD, and I keep the second 1 TB SSD as  backup.

It's crazy, this ordinals crap is really going to cripple the network as people start dropping nodes.

[Satofan44]

I accept the risks involved, which I think are minimal, and you have way better odds at ending up robbed if you use a hardware wallet as a company has now your dox plus you being an owner of a hardware wallet. The 2 laptop setup is way safer. Im just asking if there are any technical problems doing this. I assume it's exactly the same, you just have the convenience of seeing what is actually going on on your offline laptop without trusting the online node code is making it show things accurately.

There aren't any, you can definitely do this and I have done this in the past (but not in an airgap setup). Just make sure that you use very reliable media with good cables, or otherwise you will frequently run into resyncing issues. I've had those nightmares in the past, and that definitely becomes a time sink for things that should be very fast and easy to do. External SSD should work. If you were to use actual computers even in a mini factor, I would recommend connecting to SATA each time instead.

It's crazy, this ordinals crap is really going to cripple the network as people start dropping nodes.

It has nothing to do with ordinals. That does not even represent a tiny percentage of the total storage. Bitcoin's blockchain will become big due to the time-factor. It is already extremely limited at 4 MB's for the year 2026. If a user can't afford a 1TB SSDs, they do not have enough money to use Bitcoin anyway or they are completely mismanaging their finances. Don't make me bring up data about subscription services. Anyway, right now almost nobody uses Ordinals, Runes or any of that crap.