MKI and STRP

I am looking for some additional clarification with MKI and SRTP. Particularly with the implementation of the MKI. I currently have SRTP functioning with the libsrtp and Asterisk 1.8.11.0. I am just looking for answers on how to control the MKI portion of the SRTP. I have seen some reports that you would need a MIKey or ZSRTP but looking for more information on those results in more questions. Is there a way to use a MIKey or ZSRTP with Asterisk and what would be needed to make those happen? I am looking for a low cost solution if possible. If anyone has some knowledge on implementing MKi please let me know.