[Asterisk-Dev] IBM/SGI implementations

[James Sharp]

John Todd wrote:

> Speaking of off-board crypto processing, does anyone know if RTP (AES or 
> otherwise) could easily be offloaded to the Broadcom or Hifn cards that 
> are supported under some O/S'es?  (notably, OpenBSD)  Are the abilities 
> of those cards useful towards VoIP applications?  S/MIME or TLS aren't a 
> major issue as far as I'm concerned, because there typically is enough 
> horsepower on the main CPU to handle a reasonable number of requests per 
> second of just signalling.  Though processing SIP control messages in a 
> very large scale environment is a problem even for the signalling, I 
> think a more important issue is the audio stream.  Perhaps both can be 
> sped up by one of these third-party boards.  Just a thought...

Some quick research shows that it should be easy to do.

open /dev/crypto & lock it
Recieve packet.
Stuff packet into crypto data structure along with key
pull trigger on ioctl using /dev/crypto file descriptor
get decrypted packet out of structure
close /dev/crypto & unlock it
continue processing decrypted packet.