Encrypted VoIP

I am looking for a freelancer who can help me build an encrypted VoIP system using military-grade encryption. I have no preference regarding VoIP protocols, however I anticipate the need for up to five simultaneous calls. If you have the necessary skills and expertise to build this system, I would love to hear from you. Something like;

https://www.kickstarter.com/projects/620001568/jackpair-safeguard-your-phone-conversation