Encrypt outgoing data? (any mobile platform)

Would it be poss开发者_运维知识库ible 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

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/

PGP-phone has sourcecode available. You could try to be compatible with it, or just use it for inspiration.