encrypted Unix backup software

Okay, before you flame me and tell me to pipe it through
a symmetric cipher filter, hear me out.  Tape handling is
hairy, depending on what kind of functionality you want.  A regular
filter may write(2) in strangely sized blocks, not working very well
with your tape drive.

Mostly though, things get difficult when you have to/want to deal with
multiple tapes.

Although I could probably hack up "catblock" to do the job, and use
a line of the form
dump -0uBf ... | symmetric_cipher | catblock blockfactor > /dev/tape
if there exists something which already does this job, or something like it,
I'd like to know.  Now that I think about it, maybe this is the cleanest way.

PS: If there is a place where I can get reviews of the crypto software
that is out there, that'd be fab because csua just has a TON of stuff!
The "security-faq" is pretty good -- I want more! :)

Keep codin'

VaX#n8 writes:
> Although I could probably hack up "catblock" to do the job, and use
> a line of the form
> dump -0uBf ... | symmetric_cipher | catblock blockfactor > /dev/tape
> if there exists something which already does this job, or something like it,
> I'd like to know.

dd is the program you are looking for.

Perry

VaX#n8 wrote:
>
> Okay, before you flame me and tell me to pipe it through
> a symmetric cipher filter, hear me out.  Tape handling is
> hairy, depending on what kind of functionality you want.  A regular
> filter may write(2) in strangely sized blocks, not working very well
> with your tape drive.

This is what I use:

        tar -c --block-compress --sparse --atime-preserve
--use-compress-program /usr/local/bin/destape  .

and /usr/local/bin/destape looks like this:

        #!/usr/local/bin/bash

        if [ -z "$1" ]
        then
                gzip | /usr/local/bin/des -bE3
        else
                /usr/local/bin/des -bD3 | gzip -d
        fi

I also back up the des/gzip/tar to unencrypted to the start of the tape
too.


Gary
--
pub  1024/C001D00D 1996/01/22  Gary Howland <gary@systemics.com>
Key fingerprint =  0C FB 60 61 4D 3B 24 7D  1C 89 1D BE 1F EE 09 06