OK,
The Mycelium server went down a couple hours yesterday so I did not have access to my BTC for a couple hours. This got me thinking.... If thin client wallets' servers go down, will my access to my BTC be lost forever?
If this is not true, then how do I back up my wallets with Mycelium and Electrum so that if their servers go dark (from bankster hackers, government regulators, etc,), I can salvage my BTC with an alternate wallet?
Thanks,
Let me clarify: There is more than one Mycelium server, right now two, and we are expanding as demand grows. It has been a very long time since both servers were down at the same time (if ever). However one of them got stuck recently due to hardware failure, which meant that the node did not receive any blocks. During that time you would not receive any confirmations on transaction sent/received, but you could still spend and see incoming transactions. This only affected Mycelium apps that were connected to that server, and a random one is chosen whenever the app is killed and restarted.
"Keep your private keys private" has been my motto for the last few years in bitcoinland, and the same goes for Mycelium. Your private keys are only on your device, and only leave the device when you choose to...and you should, more coins have been lost due to loss than to theft.
There are two ways for you to get your private keys out of the app. The one that we encourage produces a PDF that contains encrypted private keys, here is a
sample (without the password). As long as the wallet has a private key that has not been backed up (and imported, to verify that the backup really works) it will show a "Backup Warning" button on the main screen. Annoying but necessary, we really want our users to make proper backups.
The other method uses a plain SIPA encoded private key as text and QR code, which is not encrypted, but pretty standard and supported by many other wallets. Access this method by going to the Keys tab, select your key and then the Export option.
Both methods are available even if Mycelium goes bust and the servers shut down.