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Would it be possible for me to build an application that enables people to encrypt call coming to me with my public key and then for me to decrypt the call data at my end using my own private key. This way I basically have a more secure communication channel which I am assuming because RSA is hard to crack would be difficult to monitor.

I am asking this question from a research point of view and have absolutely not considered the factor as to how computationally feasible would such an application be. I would just like to know if there is a way for me to intercept my outgoing data using any built functions.

Thanks

traumatized
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2 Answers2

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technically it should be possible with something like sipdroid to use encryption though i have not tried it on my android phone.

https://guardianproject.info/tag/sipdroid/

warsong
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  • this looks like a place to start with! Thanks, but this seems to talk about only IP data traffic. I would like to create an application that takes my raw voice data encrypt that and then pass on that data to the phones outgoing call mechanism to do what it does best. So direct voice calls can be more secured! – traumatized Sep 13 '10 at 11:48
  • i do realise that's what you were asking first time around, tbh i think that would be impractical as it would depend on whoever calls you to have the your public key. sipdroid encrypting calls would probably be the closest you will get for now. i could be wrong but what you suggest sounds a bit far-fetched. best of luck though :) if there has ever been a time when this kind of thing is possible with the openness of Android, it is now. – warsong Sep 13 '10 at 11:55
  • @Blrfl Since its not done by me, don't really trust it. If the idea were anymore ridiculous I would probably be tagged a conspiracy theorist. :) – traumatized Sep 13 '10 at 12:13
  • @warsong I was worried people might might misinterpret what I am asking coz what I am asking is pretty ridiculous and infeasible. But then its just research interest, and you never know. :) – traumatized Sep 13 '10 at 12:14
  • @Blrfl & @traumatized: GSM encryption has been compromised. not sure about CDMA, but then i don't live in america so i don't care. it is interesting and even possible, but don't think it would work due to the practicality. otherwise things like gmail would have built-in pgp encryption, but they don't because normal dumbos would find it too hard to setup a pgp key. – warsong Sep 13 '10 at 12:18
  • @warsong I am aware of that and the govt can routinely snoop in on your telephone conversation too. By encrypting and decrypting at the source and destination we can probably beat any snooping mechanism and prevent in the middle attack. Look at blackberry service facing so much flak from all the governments about security. If only we as the user decide to secure our communication, will we not be safer? – traumatized Sep 13 '10 at 12:25
  • i agree, just saying it would be impractical the way you're describing. its a good idea, but that's not the way to implement. i think there must be a better way. – warsong Sep 13 '10 at 14:07
  • @traumatized I understand where you're coming from. Hooks to insert your own crypto on the air side of the audio CODEC would be ideal, but it isn't something Joe Mobile Phone Owner cares about, carriers want to support or governments want to encourage. If you want to experiment with encrypting calls, VoIP is the platform to do it. The mobile networks and handsets aren't really designed to do what you want, and most commercial solutions use IP for transit instead of placing voice calls. – Blrfl Sep 13 '10 at 23:42
  • @Blrfl thanks for you inputs. As I said earlier it might be a 'fools errand' but I would still like to try it. :) – traumatized Sep 14 '10 at 04:13
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PGP-phone has sourcecode available. You could try to be compatible with it, or just use it for inspiration.

Will
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  • hey thanks this looks pretty close. I will use it as reference, I was actually looking for a way for me to access the data stream which is sent out of my device at realtime. Would like a way to access that to start with. – traumatized Sep 13 '10 at 11:42