How to get your bitcoins out of an old wallet without downloading the entire blockchain
A few years ago I created two types of wallets: one with Bitcoin-qt and a paper wallet with Armory. I recently started to use Electrum and wanted to recover my old wallets, but I didn't want to download the entire blockchain (which was 94GB at the time of writing). The recovery of the Bitcoin-qt wallet went fairly easy as I still had the wallet file and the password. The private keys can be exported from the bitcoin-qt console with:
walletpassphrase the-pass-phrase 60 dumpprivkey the-public-address
Repeat for all addresses that contain bitcoins.
The Armory (paper) wallet was a bit more challenging. Comments on several fora suggested that you really need to download the entire blockchain. Here is how I managed to do it without downloading it:
- Start Armory in offline mode
- Import/restore wallet (I had to restart Armory before the wallet showed up in the list)
- Double-click on the wallet
- Choose "Backup this wallet" and "Export key lists"
Step 1: verify if the generated addresses contain the bitcoins you expect to have
Armory: Uncheck everything but "Address string" and "Include unused (Address pool)" to get a list of public addresses. Import this in a client, such as Electrum, in a "watch-only" wallet to test if the balance is what you expect.
Step 2: export private keys from armory and import in another client
Armory: Uncheck everything but "Private key (plain Base58)" and "Include unused (address pool)" to retrieve the list with private keys. When you import this in another client you can transfer the bitcoins. I transferred the total balance immediately to my new active wallet, because when you keep using the wallet from the paper backup you might lose bitcoins (either due to change addresses or because your paper backup could be compromised if you got it from someone else)