ZSipOs Box

Tap-proof telephoning

All telephone calls are most likely to be tapped today. This may lead to

Loss of

  • trade secrets
  • equal opportunities (in competition)
  • the development lead
  • orders.

With more and more powerful computer chips and increasingly comprehensive software, smuggling in security holes and bugging interfaces is becoming increasingly easy.

How can this be prevented?

By using a ZSipOs box which encrypts telephone calls absolutely tap-proof.

Why tap-proofed?

All hardware and software modules in the box are open source. In particular, no proprietary CPU is used, in which the program code cannot be viewed and can contain “backdoors” or Trojans.

What does Open Source mean?

The software code as well as the programs embedded in the chips can be freely viewed and checked. Any compromise of the code would thus be public and would have no chance of success.

How does it work?

Of course, you also need a corresponding ZSipOs box on the remote station. You insert the box between the IP phone and the network
connector. Your phone is operated in the same way as before: pick up, dial, talk and hang up. When you connect to the User Box for the
first time, a “fingerprint” is created, transmitted to the other party’s User Box and displayed in both User Boxes. Then verbally check the
displayed “fingerprint” with your conversation partner for a match. If the numerical code is identical, you have a guaranteed tap-proof
telephone connection. This “fingerprint” is transferred to the boxing memory and does not need to be verified in the future.

From now on every phone call with this partner can be encrypted by simply activating the box (=press the button).

Telephone conferences

Provided that each participant has a User Box connected to their telephone, you can now hold tap-proof telephone conferences.

ZSipOs Box


This project is supported by the NGI0 PET project, a fund established by NLnet foundation with financial support from the European Commission’s Next Generation Internet programme, under the aegis of DG Communications Networks, Content and Technology under grant agreement No 825310.

NLnet FoundationNGI Zero