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I wanted to know if maybe it's possible to make a phone communication more secure than the current A5/1 (used for GSM).

Or maybe create a special tunnel between two phones. I mean like an ssh connexion or something like that.

I'm no expert at all but I just know that GSM communications are encrypted but not strong enough.

  • You can always develop your own encryption mechanisms for your own apps, or do you mean replacing A5/1? – Purefan Jun 10 '15 at 8:11
  • I mean if I want a special encryption between a friend an I and I want to call him (and the otherway) with a special encryption. I don't know if my answer is clear sorry. – Kruncho Jun 10 '15 at 8:27
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As the encryption is between terminal and MSC (mobile switching center) you can't by self change the encryption method because MSC will not understand it and will not be able to provide voice to your partner in conversation.

Of course you can use data channels (data trafic) and creating own application to implement desired encryption method. But to establish communication with your partner you will need a lot of infrastructure

P.S. You can't establish own radio communication as this will involved usage of specific radio bandwidths which are (usually) under government control

P.P.S. Some frequencies are free for personal usage (2.4GHz for example) but you are limited by law (usually maximim of 100 mW) so you will have relatively small coverage for calls

  • And can create such a "communication environnement" simply with two software defined radio devices (and some code of course) ? – Kruncho Jun 10 '15 at 8:42
  • No, for own infrastructure you will need some server(s), which will act as PBX on IP level (asterisk for example). You do not need radio devices as entire communication will be based on IP – Romeo Ninov Jun 10 '15 at 8:43
  • I believe there are some frequencies that you can broadcast at any power level (probably within reason. I imagine there is some law that prevents you from having a 50 megawatt transmitter of any frequency). – forest Apr 5 '18 at 7:49
  • @forest, as far as I know you can't use any power level. On some frequencies you can use up to 100 wats (depend on country) – Romeo Ninov Apr 5 '18 at 18:25

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