„telephone system in the cloud“ or „as software“ is the „latest shit“.

hope: voice calls will finally be encrypted… maybe yes, maybe not (sipgate per default does unencrypted UDP).

twinkle is maybe not the most comfortable gui but open source and straight forward and works pretty solid.

# tested with
   Static hostname: DebianLaptop
  Operating System: Debian GNU/Linux 9 (stretch)
            Kernel: Linux 4.9.0-11-amd64
      Architecture: x86-64

apt update
apt install twinkle
# run it non-root

apt show twinkle
Package: twinkle
Version: 1:1.10.1+dfsg-2
Priority: optional
Section: comm
Maintainer: Debian VoIP Team <pkg-voip-maintainers@lists.alioth.debian.org>
Installed-Size: 5,627 kB
Depends: qml-module-qtquick2 | qtdeclarative5-qtquick2-plugin, twinkle-common (= 1:1.10.1+dfsg-2), libasound2 (>= 1.0.16), libc6 (>= 2.15), libccrtp2v5, libgcc1 (>= 1:3.0), libgsm1 (>= 1.0.13), libmagic1 (>= 5.12), libqt5core5a (>= 5.7.0), libqt5gui5 (>= 5.2.0), libqt5qml5 (>= 5.0.2), libqt5quick5 (>= 5.0.2), libqt5widgets5 (>= 5.0.2), libreadline7 (>= 6.0), libsndfile1 (>= 1.0.20), libspeex1 (>= 1.2~beta3-1), libspeexdsp1 (>= 1.2~beta3.2-1), libstdc++6 (>= 5.2), libucommon8 (>= 7.0.0), libxml2 (>= 2.7.4)
Homepage: http://twinkle.dolezel.info/
Tag: interface::graphical, uitoolkit::qt
Download-Size: 1,487 kB
APT-Manual-Installed: yes
APT-Sources: https://ftp.halifax.rwth-aachen.de/debian stretch/main amd64 Packages
Description: Voice over Internet Protocol (VoIP) SIP Phone (GUI)
 Twinkle is a soft-phone for making telephone calls over an IP network
 using the SIP protocol. You can use it for direct IP phone to IP phone
 communication or in a network using a SIP proxy to route your calls.
 Notable features include multiple active identities, call transfer,
 call rejection, 2 simultaneous calls and 3-way conference calls.
 This package contains the graphical interface.

cross os softphone: LinPhone

LinPhone is Open Source made by the French Company Belledonne which also sells Flexisip https://www.linphone.org/technical-corner/flexisip a security enhanced sip (and chat?) service best integrated with LinPhone. (one can use other sip providers as well)

  • sipgate – while having a pretty nice web backend with loads of features (answering machine voice mail, fax pdf etc.) does not provide voice call encryption
  • hint: some providers (e.g. Vodafone) do not allow to use their LTE internet connection with other VoIP service providers (will have to test that again… Sipgate says change port)
    • Settings -> Network:
      • disable Random Port usage:
        • when connecting via WLAN use Port 5160 (UDP)
        • when connecting via LTE use Port 32160 (UDP)


luckily LinPhone desktop client comes with 3x voice call encryption methods: (tested and worked desktop <-> android app (desktop all will show a lock))

have fun testing different combinations

what worked:

  • call recording

what did not work (yet):

  • video call