The CM-STATUS feature is of significant value in DOCSIS 3.x networks. However, originally it was designed in a way it was not 100% reliable. A specification addition in March 2014 changed this messaging facility and it was further fine-tuned in August 2014. This blog post provides an overview on why and how.
Privacy is an integral and important part of DOCSIS because of the shared medium over which it operates (the HFC network). Since version 1.1, the authentication of cable modems is done using a chain of X.509 certificates (PKI infrastructure). This blog post explains the history of the different PKI infrastructures and how it will look like in DOCSIS 3.1.