Securing Your Funds With Armory

Offline Wallets

The Most Secure Way to Manage You Bitcoins!

• There is no risk-free way to manage your Bitcoins on an internet-connected computer

• Solution: Use Armory Offline Wallets– Keep private keys on an offline computer– Generate addresses and monitor incoming

payments with an online system, risk-free– Execute offline transactions using a USB key

Online attackers are no threat to a wallet that has never touched the internet!

Armory Security Model

• Your primary online system

• A permanently-offline system– Any system with 512MB RAM will work– Will never touch the internet again

• USB drive or read/write media– Anything with more than 1MB space

You can acquire an “offline” system on Ebay or Craigslist for less than $50!

What You’ll Need

Preparing the Offline Wallet

• Make sure both systems are running Armory

Preparing the Offline Wallet

• Create a wallet like normal on the offline system• Use encryption for security against physical theft

Preparing the Offline Wallet

• Make a digital or paper backup from the offline system (can use USB cable to connect to printer)

Preparing the Offline Wallet

• In wallet properties, “Create Watching-Only Copy”• Save watching-only wallet to USB drive

Preparing the Offline Wallet

• Transfer USB to online system, import into Armory• In wallet properties, click on “Belong To” field• Check “This wallet is mine”

Preparing the Offline Wallet

• The online system now produces identical addresses as the offline system!

Preparing the Offline Wallet

• Track transactions the same way as a regular wallet• Even if online computer is compromised the attacker cannot

spend any of the funds!

Executing an Offline Transaction

• The online system can create an “unsigned transaction” which is much like an unsigned check

• Save to USB and copy to the offline system for signing

Executing an Offline Transaction

• Use the offline computer to sign the transaction• Transfer the transaction back to the online system

Executing an Offline Transaction

• Finalize the transaction by broadcasting it to the Bitcoin network from the online computer

• It will be processed and verified like any other transaction!

Extra Notes

• The watching-only wallet only reveals the linkage between all the addresses generated by it

• Compromise of the watching-only wallet is a breach of privacy but not a breach of security

• The transaction data transferred via USB is not sensitive

• It is acceptable to use plain email or borrowed USB drive to transfer transaction data

With a little practice you will be executing offline transactions in under one minute!