I am going to post in this thread my experiences in getting my Desktop (Debian) machine running Armory in watch-only mode, and coupling that with an offline Raspberry Pi (which holds my private keys) for signing the transactions previously made in watch-only mode.
I actually compiled Armory from source directly on my Pi. This guide is probably more for the bitcoin 'power user', as to run Armory online, and broadcast the signed transactions, you need to have a bitcoin full node running (bitcoind).
- Online machine - running a full node (bitcoind)
- Raspberry Pi - I used an old Pi 1 Model B with just 512Mb memory, and 2 USB slots.
- 2x USB thumb-drives. One for wallet backups, the other for transferring unsigned tx's to the rPi, and signed tx's back to the Desktop.
- Armory 0.96.4 for the Raspberry Pi 1, Model B (512Mb RAM, 2xUSB) (compiled from github sourcecode on the Pi itself!)
- Using the Pi as an offline complement to a Debian Desktop "watch-only" Armory install.
- Desktop Debian Armory watch-only talks to my full node, bitcoind, which is also on the Debian desktop.
I'll post the guide in digestible sections...
I should begin by saying I installed source code from git, and got Armory to build the DB on my desktop initially, WITHOUT creating a wallet.. (This allowed me to debug what was going on a little!)
- I am using Armory 0.96.4
- Desktop: Debian 9, Dual-Core, 2Gb Memory, 2Gb Swap.
- Pi : Pi 1, Model B (512Mb RAM, 2x USB, Ethernet)
Go to Bitcoin.org, select Armory..
It leads to a Download from Git: https://github.com/goatpig/BitcoinArmory/releases
Followed the procedure for Linux Debian verify code, compile, install, all straight-forward..
Began by running bitcoind, and telling Armory where to find it. This is the command I used, obviously it was all on one line and didn't include the arrows/explanations!:
python ArmoryQt.py \ --satoshi-datadir=/BlockChain/chain20180414/blocks \ # <-----(where my bitcoind blocks live) --datadir=/ArmoryDataDi \ # <-----(this is instead of ~/.armory) --dbdir=/ArmoryDataDidatabases # <-------(again, non std. place used for Armory's databases.. my choice.)
So, on the Desktop, after the initial "build databases"
(NB the initial "Build Databases" took about 1.5h and my two CPUs were maxed the whole time, Temps up to 62C. Not ideal; Im not in a rush!)
I then wanted to import a watch-only wallet.
Before I did this, I took a full backup of the Armory data dir:
(or ~/.armory in a default installation).
I'd hate to have to make Armory do another full sync with the bitcoind node!
Next step: offline wallet (with Private Keys) is on a Raspberry Pi.
I downloaded the source and managed to compile it on the pi itself! :)
Though there were some gymnastics needed to setup the Pi.
My Pi is running Raspbian based on Wheezy.. quite old!
I did the following on the Pi:
apt-get update apt-get upgrade (<---took about an hour!) apt-get install autotools-dev apt-get install autoconf
Then I followed the instructions exactly as I had done for my Debian Desktop machine, EXCEPT:
I had to increase the Pi's swap space. I upped it from 100Mb to 400Mb.
The compilation took 7 hours, and my poor SD card got a thrashing.
But after compilation, I put the Swap back to 100Mb and Armory runs ok with about 150Mb of memory (no swap needed).
Swap increase on the Pi:
use your favourite editor, and open the file /etc/dphys-swapfile
add/change the following line:
Then, REBOOT the Pi:
sudo shutdown -h -P now
Once the compilation was done on the Pi, put the swap back, rebooted and created an Armory wallet.
I added manual entropy and upped the encryption 'time' from 250ms to 2500ms - since the Pi is slow, but I'll be happy to wait for more iterations in the Key Derivation Function.
Once the wallet was created, it obviously prompts you for backup.
I want to add a private key of my own (i.e. import), so don't do the backup until this is over.
I import my Private Key, and Armory checks that this corresponds to a Public Key, which I check is correct.
This is the point now where the Pi storage medium (e.g an SD card) has to be properly destroyed if you ever get rid of it.
I had thought that now would be a good time to decide if your new wallet will generate Segwit receiving addresses, and also addresses used to receive 'change' after a transaction..
But it seems Armory WON'T let you switch to P2SH-P2WPKH unless your Armory is connected to a node offering "WITNESS" service.
Obviously, my Pi is offline and will never connect to a node, so the following will not work on the Pi:
- x Use File Settings Fee and address types.
- x Set the "Preferred Receive Address Type" to P2SH-P2WPKH
- x Also Set the "Change Address" to P2SH-P2WPKH for left-over loose change!
NB: I thought about setting this on the Debian "watch-only" wallet, but that would surely mean doom, as the Pi would not know about those addresses and backups might not keep them.. who knows...
So, end result:- no segwit for me just yet in my offline funds.
--If anyone can offer a solution to this, I'd be very grateful--
Ok, now this is a good point to back up your wallet on the Pi. It has your imported keys. I choose a Digital Backup - and put it on a USB key, which will never touch the internet and will be stored off-site. I also chose to encrypt it, because I'm good with passwords..
NB: The Armory paper backup will NOT back up your imported private keys, so keep those somewhere if you're not sweeping them. It would be prudent to have an Armory paper backup anyway, but remember it will likely NOT help you with that imported key.
Now for the watch-only copy of the wallet. I want to get the "watch-only" version onto my Desktop Debian machine.
On the Pi, I created (exported to a USB key) a "watching-only" copy of my wallet.
I would use the RECOMMENDED approach, export the "Entire Wallet File".
As you will see below, I initially exported only the ROOT data, which will NOT capture the watching-only part of the Private Key I entered manually above (i.e. the public Key!).
Now, back on the Debian Desktop machine...
I stopped all my crontab jobs; just give Armory uninterrupted CPU/memory/disk...
I also stopped bitcoind and made a backup prior t