At a time of heightened national security and privacy paranoia, Switzerland holds all the aces. Not only does it have a culture of keeping secrets, but it is also home to a group of physicists who appreciate the universe’s predilection for privacy.

Tim Berners-Lee, the man widely credited with creating the internet during his time working at Cern, the particle physics facility in suburban Geneva, has publicly called for programmers to develop better, more user-friendly cryptography. That way, he says, we can all get back to living private lives again.

Interestingly, it is out of Cern that the best hope for the fulfilment of that vision may arise. A gaggle of its particle physicists became so concerned at last year’s revelations of mass surveillance by the US National Security Agency (NSA) that they decided to do something about it. The result is ProtonMail, an email encryption service that Forbes describes as “the only email system the NSA can’t access”.

That inaccessibility is partly because ProtonMail’s servers are in Switzerland, where the law prevents government agencies from gaining access to them. It is also partly because the servers won’t even contain decryption keys. But mostly it’s because maths shows that it’s not hard to conceal information if you know what you’re doing.

There are ways to perform reversible mathematical operations on data that will render it indecipherable to prying eyes. As long as you have the key – that is, you know exactly what the mathematical operation was – you can undo the obfuscation. If you don’t have the key, there is no way to winkle out the original data. In many ways, it is astonishing how reluctant we are to take advantage of this. But things do seem to be changing.

ProtonMail was quickly oversubscribed – there is a waiting list for accounts even though the system is still in its beta-testing phase. The company has rejected offers of investment from venture capital firms. Instead, it raised more than $500,000 through crowdfunding.

In August, ProtonMail held a hackathon at the Massachusetts Institute of Technology. The idea was to improve security by allowing the experts to look for weaknesses. Now, with that exercise complete, a more secure version will be released. The aim is to make it open-source, so that its code can be checked and strengthened.

The laws of physics actually allow researchers to go much further than maths-based encryption. The technology known as quantum cryptography uses a fundamental rule, one that governs the smallest scales of the natural world, to achieve the ultimate freedom from eavesdropping.

When nature’s basic particle building blocks interact, in the right circumstances, they can become “entangled”. Information encoded on entangled particles is shared between them. In a weird twist of nature, these particles can retain a link even when separated physically. It’s almost like a telepathic connection: reading the information on one can affect the other in ways that allow monitoring of any eavesdropping activity.

Physicists have exploited this to create tamper-proof seals for information encoded on photons, the particles that make up light. The technology is not yet perfect, but it’s good enough that it is starting to be used for financial transactions and various other sensitive communications. The market leader, ID Quantique, was developed at a fundamental physics lab based in – you guessed it – Switzerland.