[Asterisk-Security] How does native IAX encryption work?

[Brian Capouch]

steve szmidt wrote:
> 
> I got this back from Mark (while he's in the air at 30,000 ft):
> 
> Instead of using the md5sum of the challenge + password being 
> sent back for the authentication, it is used as an AES key.  16 bytes of 
> random data are prepended (staring with random data, continuing with the 
> last 16 bytes of the previous packet).
> 

So how does one configure it?  Does it need special keys defined 
somehow?  Are there any knobs?

I expect I'll start reading the code, but I was hoping to leverage off 
of someone else who has already been there. .

Thx.

B.