End to End encryption security
Very high security risk context represent a typical scenario for end-to-end encryption.
Usually end-to-end encryption is required by government agencies or small group of “secure” speakers to protect mobile phone calls against wiretapping.
Protection is extremely strong and goes directly from caller mobile phone up to called mobile phones, without any chance for intermediate devices (PBXs, routers, switches, firewalls) to be able to listen to the call.
That’s the strongest security model, called end-to-end encryption and we enforce it with ZRTP protocol.
ZRTP is the open IETF standard voice encryption system invented by Philip Zimmermann that requires human-based verification for the encryption of a call.
To simplify with an example: