Update; We've added more info about our Offline Bitcoin Toolkit, it allows you to backup, sign transactions and generate any/all Coinkite multisig keys offline!
Back-up (Key Escrow), Generate Keys and Sign Transactions Offline
For additional security we offer theses downloadable files for use while off-line.
We provide this stand-alone, in-browser key generating tool, which creates a new random BIP32 ‘wallet’ to be your private key for the new wallet. The secret values that it picks are easy to print from the tool (for paper backup), and for storing on computers, we help you pick a secure passphrase and encrypt the file for you (using AES-256-CBC).
The resulting encrypted keyfile is verifiable, meaning if you have a little Unix background, you can be 100% sure that the key is encrypted using AES-256-CBC and with only your key.
Back-up and Key Escrow
The encrypted keyfile can be uploaded (one click) so that Coinkite can store it forever, and then we can decrypt it and use the key inside to authorize transactions very easily. The encrypted file can also be used offline without giving it to Coinkite if you wish.
Air Gap
Because we have delivered this “key generating” tool as a standalone Javascript/HTML file, you can use it on any computer with a browser. You can put the program onto a USB flash drive, and run it later, or on another computer or whatever. You do not have to trust us that we didn’t peek at your private key.
Read up here
https://coinkite.com/offline/
