How do you clone a drive encrypted with Filevault2?

Question

Say I have drive A that is already encrypted with Filevault2. I want to make an exact clone of the drive to a different drive B. Every way I've tried so far decrypts drive A first, then clones, resulting in drive B being decrypted when the clone completes. Is there a better way to clone drive A bit for bit? I'm thinking of using dd but was wondering if there was a more Apple friendly way.

The best way I've been able to figure out how to do this so far:

1. Boot to a Lion install USB drive.
2. Open Disk Utility & unlock the encrypted drive
3. Format the new drive
4. Restore the encrypted volume on your new drive. It will be unencrypted.
5. Close disk utility & open Terminal.
6. In Terminal, type "diskutil cs convert /Volumes/Macintosh\ HD/".
7. Boot up to the new drive, open System Preferences, & re-enable encryption. All previous settings should still be there.

I have not fully tested this method, but in theory it should work. It's too many steps for my liking though. I'd prefer one clone & be done with it, somehow.

Answer 1

You could use the recovery option of Disk Utility:

This of course requires source and target disk to be identical, but the same restriction applies to dd and similar tools.

Usual warnings concerning picking the right disk as source etc. apply!