Bitcoin Forum

I don't have a computer dedicated to using Armory offline, but I've noticed something about Armory that makes me question how usable it'd be in an offline computer.  Whenever Armory is in offline mode, it won't show me the balance of my wallets.  If this is also the case in totally offline mode, it doesn't seem like the user interface of Armory would be very useful.  After all, how useful is the offline client if you don't know how many BTC are in your wallets? 

Is this how Armory works in offline mode, or is there some trick I'm not aware of to getting the balance to show up when Armory isn't online?

You're right, it doesn't show your balance offline.  But it doesn't need to know your balance.  You only need that to create the transaction, which is done from the online computer.  Once the transaction is created (and a bunch of other verification data is bundled with it), the offline computer has everything it needs to know to determine "This wallet is sending X BTC to address Y with fee Z."  Then it allows you to sign it.

That's all the offline computer does:  lets you confirm the transaction details, and sign it. 

You can think of it like writing a checking that requires the signature of someone locked in a vault.  The person in the vault doesn't know how much money is in the bank account because they have no access.  But the check isn't valid without their signature.  So you go into the vault and they say "This check is sending X BTC to addr Y, is this what you intended?".  You approve, they sign it, and then you leave the vault and take the check to the bank (broadcast to the network). 

This makes a bit more sense now, but I'm still having a little bit of a hard time wrapping my mind around this.  Let me see if I understand this correctly.  Basically, the online computer says I want to send x amount of bitcoins with y transaction fee to z address.  The offline computer then looks at that and lets you say, yes this is correct, signs it, and then lets you broadcast it on the online computer?  I'm basically just restating what you said, but I want to make sure I'm understanding it properly.

Have you seen this?

https://bitcoinarmory.com/using-offline-wallets-in-armory/

I've read it before, just didn't click through the slideshare portion previously.  This makes more sense now, thanks again.

Also thanks again for answering the total newbie question.  It's just a little hard to wrap my brain around without actually carrying out an offline transaction, and I don't have an offline computer yet to do that with.

You just need to install linux on a USB drive -- you can boot to that as an "offline" computer.

Huh, neat.  I didn't know you could do that.  Wouldn't that be a lot more of a risk of acquiring viruses if it's installed on a flash drive than if it's a separate computer?  Ideally my computer will never get compromised, but this seems somewhat less secure than the traditional method.  I suppose there's a bit more security in that it's linux rather than Windows which I've got on my regular computer.

The only time it's at risk is when you download the linux image and then while you're installing armory -- from then on you disconnect the network and it's stand alone.  So it's about as secure as you get without some craziness.

If you install Ubuntu 10.04 then you can use the offline bundle from the downloads page that has 100% of the dependencies included.  I've tested it:  it installs successfully in a completely first boot fresh install of 10.04, without any internet connection.

I will eventually make offline bundles for other versions of Ubuntu, but I picked that one because it will work no problem even on ancient hardware.  It's just that it's a lot of work to setup an offline bundle, so I haven't gotten around to the other versions yet.

Nice!  I didn't notice that previously when looking at the downloads page.  While I can't speak for all Armory users, I personally would rather you work on updating Armory itself than creating more versions of Armory for other versions of Ubuntu or one of the other half a billion Linux variants.  At least it seems like there are that many, anyway.  I'd say one is enough personally, but that's just me.

It used to be a lot of work, but now that I have most of release process scripted, I can do it much more easily.  Rather, it used to be a lot of work to recreate and re-release each bundle, which is why I only did so every 4th version or so.  Now that the process is scripted, I only have to put in effort once to create the original bundle, and then it's really not much extra work to include them on every release.

Ubuntu 10.04 is becoming pretty seriously outdated, so I'd like to at least create one more 32/64-bit pair of bundles to support a more-modern Ubuntu version.  After that, the one more bundle I need to [figure out] and create is a Raspberry Pi bundle.  I finally even got a RPi, but have had zero time to play with it!  One day, though...

Don't worry, my efforts right now are focused on the new Armory version.  It's kinda slow.  But steady...