Surveillance camera, such as the Nest Cam, provide live stream of feed. Now given such a device which is always connected and streaming what kind of network security model do such products employ?
I assume such products cannot afford to let the stream be eves-dropped or tampered.
Dropcams and Nest Cams connect to the Nest cloud service using 2048-bit RSA private keys for key exchange, implement perfect forward secrecy and encrypt data between Dropcam/Nest Cam and the Nest cloud service using AES 128-bit encryption and Transport Layer Security (TLS).
https://nest.com/privacy/data/
Though, that is not enough, there are some known vulnerabilities found already, published here. The Nest privacy page introduces a bounty program for researchers to find more for fixing and they have a dedicated team to that research, too.
The default operation of the camera(s) may not be secure. If security features are enabled, it will likely include authorization and encryption to get at the video feed.
However, your are best assuming that even with security features enabled - your cameras are not secure. There are back doors baked into these products on many levels before the device is ever assembled. This is widely reported already.
If you want to keep something secret, do not record or transmit it.
