Brainstorm

This is how I would like the backup application to work.

1) Start backup application.
2) First start up -> key generation (private & public)
(passphrase for privatekey optional)
3) Ask local backup destination (only location on SD card should be allowed)
4) Ask backup interval (1/week, 1/day)
5) Ask which content is to be back-upped
6) Ask if backups are to be auto synced to online location over
- WLAN connection
- Phone data connection
7) Finish.

After this device would automagically do (incremental?) encrypted backups to
the SD card on given interval.

Incremental backups could be done with unencrypted index that has filename ->
hash so we would know if some file has changed and need to be on next backup.
If we wish to be more secure even filename would not be needed in index. hash
of it or inode information would be enough to match.

I know there is online Ovi backups, but I think something like this would be
beneficial for the users. Especially if they are not able to sync for few days.

Lot improvements there
- like where and how to store the private key. 3 security levels there.
1) leave it on device
2) leave it on device if it has passphrase
3) store it elsewhere and delete it from device altogether.
- How to make sure that we do not take too much space from SD card
(allow only backups over 1 week?, allow only backups to take x% or xMB from
card?)
- notify user as backups have been completed.