This browser is based on Firefox and has several levels of encryption. It uses the Tor network to protect your identity – even the websites you visit cannot tell who or where you are, only that you are using the Tor network for access.
Some sites and platforms are specifically secured for use with Tor. This is represented by domains ending with .onion, which are not accessible using a standard browser. Wikipedia shows a list of some of these Onion services, and links are available on GitHub. When you hear about the "dark web", it is usually a reference to onion services.
Tor is banned in China and several other countries. This leads to a virtual arms race in which TOR develops ways to bypass such blockades.
Sadly, Tor is managed by the Tor Project, a non-profit organisation based in the United States, which may become vulnerable to the current US administration.
VPNs act as tunnels that encrypt and contain/hide your data on the way from your computer to your VPN provider, before accessing the original target website or service. When VPN software is running on your computer:
Like TOR, VPNs are banned in some countries.
The IHEID VPN
This VPN can be used:
It is a selective VPN, meaning that it ignores data that is not directed towards the Institute or its subscriptions. It cannot help you hide your IP address from other platforms, nor simulate a Swiss presence to circumvent geolocation on websites not related to our network or subscriptions.
Other VPNs focused on security/privacy for activists and researchers working on sensitive topics
Using other VPN services could help you access data that is restricted to specific countries (geoblocked content) or just hide your identity when consulting sensitive resources.
The problem with most VPN providers
Other popular VPNs could be appropriate for other purposes (especially watching geo-blocked media), but their policy, reputation, and headquarters are things you should verify before adopting one: they might be making matters worse if what you are concerned about is security and privacy.
Unlike TOR, some VPNs require identification and some providers keep a trace of your data usage, which makes you vulnerable if they are hacked or if they have bad intentions themselves. VPNs based in the USA are also vulnerable to legal requests by the surveillance authorities. You should not use a commercial VPN without vetting it first if your main concern is security and privacy.