One of the modes of Casascius' BIP-0038 key encryption standard is the non-EC-multiply mode, which can be used to encrypt an existing private key with a passphrase.
Unfortunately, if you would like to use this mode to generate nice printed bank notes with an encrypted version of the private key of one of your existing cold-storage accounts, the BtcAddress app reference implementation does not support this - it only supports creating notes containing brand-new encrypted keys. The underlying code is already there, but the GUI does not support it.
Therefore, I have made enhancements to the BtcAddress app to provide GUI support for printing banknotes of encrypted keys generated using this mode.
Some links:
Some screenshots:
(New menu item.)
(New dialog box.)
Caveat: The "compress public address" option does not work yet.
(Some data filled in.)
(Resulting encrypted key in collection.)
(Example of a bill that can then be printed - not the same example.)
Obviously, this capability ought really to be included in the master branch of the reference client for better trustability, and hopefully Mr. Caldwell will honor that pull request.
First, the diffs need to be cleaned up a bit - there are a few accidental/unnecessary/inconsequential changes in several files (line-end changes, commented-out code that wasn't used) that are unrelated to the new feature. The only actual important changes are in the new form AddEncryptedKey and the corresponding changes in the top-level form to add the new menu items.UPDATE 12/3/13: In the below branch, I have now cleaned up the diffs (reverted inconsequential changes) and submitted it as a pull request.
Comments/tips are welcome...
