Connect secure and non-secure user

Hi ,

I have two question regarding a situation when two clients tries to make a call (one offers srtp while 2nd one does not support).

The client i am using have only SRTP enable/disable (no option such as optional/mandatory).

while calling any one, i want to see what transport i am on and what transport callee has (tls or udp), after that i can make a logic to handle that call and enable/disable srtp on dialplan.
So, the question is , can i get transport type of both peers in diaplan/AGI.

My 2nd question is , lets suppose we do not have any way to get transport type, how can i make it possible to make a call between srtp and non-srtp user.

Thanks

Asterisk is a back to back user agent, so is man in the middle to any media level encryption.

thanks david.
Could you please explain your point?

Asterisk always decrypts (there may be some special direct media cases, but certainly the default is to decrypt) os even if you had two SRTP legs, they would have different session keys.