Secure VoIP

Question

Encryption

Good afternoon, an ambitious task has appeared in the field of VoIP, which, unfortunately, I do not understand well.
1. It is necessary to organize VoIP between mobile phones and computers
2. Voice transmission must be encrypted
3. software must be opensource
4. Availability of sane clients for Windows, Andorid.
*5. It is desirable that users were able to transfer files (up to 5 MB), which are also encrypted during transmission.
*6. from 10 to 100 users in total.

For the user, all this splendor should be no more complicated than Skype ...
I read pediviki, there are such solutions, I would like to hear feedback from specialists who used / implemented such solutions.

Thank you!

Answer 1

Asterisk 1.8 + Bria. There is no file transfer, there is encryption.

Answer 2

If the mobile phone is a smartphone, then it’s business for “five minutes”, an OPENVPN server is created, all computers and a mobile phone connect to it. And in this Internet tunnel we transmit any traffic, even voice or some other. in a nutshell, here it is.

Answer 3

+1 but instead of openvpn it is better to use pptp, it is more native for smartphones

Answer 4

A quick, but not convenient, organization of secure calls was done in a hurry with us as follows:
inside the office there was an asterisk (internal ip),
one of the external IPs was configured on a piece of hardware from cisco, on which the vpn server was configured.
on mobile phones vpn client part.
The algorithm was as follows:
1. connect to the vpn
2. launch the sip client on the mobile phone and speak The
inconvenience is that every time you need to connect vpn in order to talk.
Z.Y. This is a little more detailed in the first comment.