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Re: How can I create data DVDs with encryption (AES preferred)

Meino Christian Cramer wrote:


I am using growisofs/mkisofs to create my data DVDs.
Now I want to encrypt them. With my CDs I used loop-AES for this
purpose, but I haven't found a way to do so with growisofs due to
the different workflow.

Thank you very much in advance for any hint or trick or help to
achieve this.

The problem revolves around your choice of writing once or being able to grow. If you wish to grow I would have to wait and see if someone has a really good way to do it, while for writing a one-shot DVD, it's simple.

Create a file the size of the filesystem you want to write. I suggest that filling it with /dev/urandom will be a bit slower than /dev/zero, but may (or may not) make it harder to break. If you're just trying to have a minimum level of security it probably doesn't matter. Then mount it with loop-AES, cryptoloop, whatever you like. Now write your data to the image, using mkisofs or creating an ext2 filesystem and mounting that. For excrypted backups that's often easier, since you can just copy data.

Then unmount and just burn the file you created. It can be mounted (at least with cryptoloop, haven't tried loop-AES in over a year), and read just fine.

Extrapolation: using ufs and DVD-RW you can have a live encrypted filesystem. I have not tried this, but several people have written that it works.

I do backups that way, I take a du of what I want, break it into 4400MB chunks with breaker, and then let a script create each filesystem and burn the DVD. For 12GB of data it's practical, but I am waiting for Blue-Ray 50GB media to to anything of serious size.

bill davidsen <davidsen@tmr.com>
 CTO TMR Associates, Inc
 Doing interesting things with small computers since 1979

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