hi,
I would like to implement a secure channel over an unsecure medium.
mic(voice) => A/D conv =>digital, unsecure, unknown comm link => D/A conv =>voice analog Host A/D digital "other side"
I do not want to encrypt data at the device's digital side because it is unsecure, and I dont know how to interfere digital data I don not have access to embedded software, source code etc. (maybe just after host A/D converter and emulating Host A/D converter to device,,,maybe) and every encryption algorithm implemented here can be broken at the other side I guess.
What I want to do is ;
mic(voice) => A/D conv + cpld or fpga + D/A conv =>A/D conv => unknown comm link analog ecrypt + scramble digital data voice like encrypted signal
The Device will see voice freq signal and will transmit them through channel as if they are real voices. At this point adding some noise may help a lot. a little bit noise may fool attackers but human still can understand what is said.
questions:
what is possible weakness of this system? I am sure it can be still broken but how easy to break it? What kind of tools/approaches "they" are using ? Is cpld enough for general data encryption? (data is human voice so 8Kbps.) encrytion should be easy so the hacking also.... they: whatever you say
thanks
yusuf