ProtonMail, the encrypted service designed by a group of scientists formerly employed at CERN and MIT, has announced the public release of ProtonVPN – a new virtual private network (VPN) built "in response to increasing online surveillance and threats to net neutrality".

A VPN lets users browse the web without being tracked, circumvents censorship blacklists and passes internet traffic through an extra layer of encryption. They have become popular in the post-Snowden world, where hungry tech firms are gobbling up data on an unprecedented scale.

In recent months, the world has witnessed the repeal of Obama-era rules designed to protect consumer internet browsing history and the attempted erosion of security by the global political establishment's position on encrypted messaging applications such as WhatsApp.

"In the past year we have seen more and more challenges against internet freedom," said ProtonMail co-founder Andy Yen in a statement this week (20 June).

He added "now more than ever, we need robust tools for defending privacy, security, and freedom online".

The company behind the software – Switzerland-based Proton Technologies – is offering both paid and free versions, the latter likely being offered to bulk up the total userbase. Paid tiers boast "seamless integration" with Tor, a network used to surf the web without being watched, the firm noted.

"Strong encryption and privacy are a social and economic necessity," Yen said. "Not only does this technology protect activists and dissidents, it is also key to securing the world's digital infrastructure. We're committed to making online privacy a reality again for all internet users."

The VPN has reportedly undergone rigorous testing, with 12 months of development and four months in a beta stage being analysed by more than 10,000 volunteers. ProtonVPN operates under Swiss jurisdiction, meaning it is protected by some of the world's strongest privacy laws.

The firm said the ultimate aim of the software is "to better protect the activists, journalists, and individuals who are currently using ProtonMail to secure their online lives". At the same time, it called out some of the biggest technology companies in the world.

It said "unlike Google and Facebook who abuse user privacy to sell advertisements, ProtonMail and ProtonVPN are entirely dependent on users upgrading to paid accounts to cover operating expenses". The company said it relies on direct user support to help fund projects.

However, paying for the VPN will give you slight perks over other users. According to its website, higher tiers lets users connect more devices, provides higher speeds of use and access to enhanced servers. Paid options range from $4 (£3) per month to $24 (£19) per month.

You can see the full list of pricing and availability options here.

"The best way to ensure that encryption and privacy rights are not encroached upon is to get the tools into the hands of the public as soon as possible and widely distributing them," Yen stated. "This is why we're committed to making a free version of ProtonVPN available to the world."

The release comes as VPN software is being outlawed in many countries – including Russia and China. And consumers need to be careful about what firm they turn to for protection these days. In April, a study found "hundreds" of apps online claiming to offer security were useless.

ProtonVPN is available on all devices including PC, Mac, smartphones and some routers.