A hardware filter called Winston that users plug into their modem to protect their data has launched, in response to mounting concern over digital privacy and surveillance.

Created by US start-up Winston Privacy, the filter promises to prevent online tracking and profiling for every member of the household where it is installed, and across every device on the network.

This includes smartphones and smart-home products like connected fridges and speakers.

By scrambling, encrypting and anonymising the flow of data, Winston eliminates a raft of intrusive or annoying aspects of online browsing.

One of these is airline price bumps, where ticket prices rise after a user's initial visit to a website to entice them into panic buying. Another is price manipulations, where retailers show different prices to different customers based on their past online behaviour.

Although there is an existing patchwork of software that can perform similar functions, Winston is different in that it is designed to be a simple, plug-and-play solution that anyone without tech knowhow can use.

It is effectively virtual private network, anti-spyware, anti-malware, firewall and ad-blocking software in one.

Users plug it in between their modem and router, and one minute after they turn it on, the device should be effective.

Winston Privacy identifies big tech companies, advertisers, data brokers, governments and hackers as parties its users would have an interest in blocking.

Founder Richard Stokes came from the ad-tech industry and started the company after watching technologies that track, mine and sell private information rise to the fore in that space.

"With every post, click and purchase, we have become the product. I didn't agree to that, and I bet you didn't either," wrote Stokes in a column for Fast Company. "We need a combined political and technological solution to unwind this surveillance economy."

In the year since the Facebook and Cambridge Analytica scandal raised awareness among people of how their data was being collected and used, there is also appetite for such a product.

Winston raised more than US$500,000 when it launched a Kickstarter campaign earlier this year, and is extending that with further crowdfunding via Indiegogo.

It works by routing the household's web traffic through 20 to 30 other Winston units that are randomly selected several times each hour. This makes it impossible to correlate individual users to their IP addresses.

As well as the hardware filter, there is a software component to Winston that users access through an annual subscription.

Along with stopping surveillance, Winston blocks ads on most devices, resulting in faster load times and an up to 45 per cent drop in data usage.

Winston Privacy says its system is designed as "zero-knowledge", meaning no-one at their company can access or sell the data of its users.

The product follows on from last year's launch of the Helm Personal Server, created with New Deal Design, another piece of hardware designed to bring high security to home internet connections.