Has anyone out there modified the bridge code to do encryption/
decryption?

I'm working on it, but if it's been done already that could save me some
time.

What I'm doing is a setup where all traffic to a given MAC address would
be AES-encrypted with a unique key. Traffic from that address would be
decrypted using the same key.  Other than encryption and decryption, the
bridge would be transparent (or, could drop all packets for which
encryption keys are not known, if you want to disallow cleartext).  

Why am I doing this?  Well, one use would be secure transparent bridges
over wireless or optical links.  That would require an encrypting bridge
at both ends.

You may point out that this sort of thing is better done with IPSec,
tunnelling, or other components of the Linux IP stack.  That may in fact
be true in many cases, but I actually have a different use in mind for
this code.  However I can't talk about it until the company I work for
announces it.  :-)

I'm not doing key management at the kernel level - I am modifying the
brctl program to give a command line interface, but that is just a
simple wrapper around a new ioctl for the bridge.  In reality a
higher-level protocol and application would be used to manage keys.

My work will be GPL'ed of course, but not done or released yet... maybe
in a week or two.  I've stolen code (hashtable stuff, etc)  from the
mac-filter patch for the bridge code, and the AES code is from the
Loopback-AES kernel patch.

I have to thank the authors of the bridge module and the macfilter patch
for writing such readable, easy-to-hack code...

If anyone has done this before, or is interested, drop me an email...

Torrey Hoffman
[EMAIL PROTECTED]


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