It will establish a good foundation for security, but how well it will protect your privacy is still a bit unclear. The Matter standard uses blockchain technology, the same tech behind cryptocurrencies such as bitcoin, to verify that devices are legitimate and not potential bad actors. The standard also requires all data being transmitted between devices to be encrypted.

“Unless it’s secure, it’s difficult to say that you can exert privacy controls either by the consumer or by the manufacturer in an appropriate method,” says Tobin Richardson, the CSA’s CEO and president. “So our focus mainly right now on the privacy side is to make sure that it is as secure as possible.”

So for now, you should consider the privacy protections of the ecosystem(s) you choose to use to control your Matter devices. For example, Amazon and Google have faced criticism for logging the state changes (turning a light on or off, setting the thermostat temperature, etc.) of every smart home device connected to the Amazon Alexa and Google Home systems, even when you don’t control them from Amazon and Google devices. However, Apple HomeKit is designed in such a way that device data can be accessed only from your personal Apple devices, even when stored on Apple iCloud servers.

“We strongly support the idea of interoperability, but in order for consumers to trust it, privacy values really need to be incorporated,” says Justin Brookman, director of technology policy at Consumer Reports. “It’s great if different devices can talk to each other, but if there aren’t limitations on what all those companies can do with your personal data, interoperability actually introduces a lot more privacy challenges.”

Brookman compares it to what happened with Facebook and Cambridge Analytica. “Facebook used to be a lot more open, letting third-party apps collect and use all sorts of data,” Brookman says. “But if there aren’t rules and enforcement in place, bad actors can get access to information they shouldn’t have.”

Source: https://www.consumerreports.org/smart-home/matter-smart-home-standard-faq-a9475777045/