You may think that you have all the basics of security covered, with a firewall, antivirus and a bit of common sense to make sure that your internet-connected devices, whether they are laptops or mobile, stay as safe as possible.

Nothing is 100 per cent guaranteed to prevent an attack, but you’ve taken the steps you can to keep your data secure on your device.

But what about the data that is being sent over the internet to and from your devices? That’s where a VPN can be useful.

What is it?

A VPN, or virtual private network, provides a secure, encrypted connection for your web traffic, connecting your laptop, tablet or smartphone to its servers, allowing you to protect your data and privacy. It’s a group of computers networked together over the internet.

Why do you need it?

There are several reasons for using a VPN. If you work for a large organisation that supports remote working, you might already be familiar with VPNs as a way of securely connecting to your company servers. However, there are VPN services that are specifically targeted at individual users. Maybe you want to protect your privacy online; perhaps you are based in a region where government control of the internet is tight and you need to take steps to keep yourself as anonymous as possible.

For the average consumer, the idea of using a VPN for normal web browsing might be overkill. However, if you are a fan of using public wifi hotspots, a VPN might be worth considering.

Think about it. You are sending and receiving information over an open network. Maybe you’re idly browsing news websites while you wait, or researching your next holiday. You could be checking your email. Perhaps you’re even paying a few bills while you can.

However, the login requirements for the hotspot are minimal at best, and you aren’t sure what, if any, encryption is on the data. That means protection for your web-browsing data is low, and it’s vulnerable to being intercepted by anyone with the right tools and know-how. And although some websites may offer a certain level of encryption for your data, such as passwords and authentication details, it’s only as secure as its weakest link. That’s why sites such as Twitter use hypertext transfer protocol secure (https) for logging in, a change that it implemented for its web interface in 2012.

But if this isn’t available, a VPN service can help. It encrypts the traffic for you, keeping it safe from prying eyes.

Another use for VPNs is to circumvent geoblocks used on legitimate services. For example, if you pay for a streaming service, the library of content may differ depending on your current country and in some cases is not available to access at all. If you travel a lot, that can be a bit of a pain.

Netflix, for example, has a wider library of content available to its US users than in other countries, with the result that many users use VPNs or alter server settings to make it seem as if they are in the US.

It’s a practice that looks as if it may be coming to a halt, with reports last month that Netflix was preparing to block access to VPNs. That’s something the company has since denied, but it has come under pressure in recent months from copyright holders who want the streaming video service to take tougher action to prevent people from accessing content through VPNs.

Other services, however, have taken a tougher line on VPNs to keep users who shouldn’t be able to access their services from doing so. Television streaming site Hulu has barred IP addresses known to be used by VPNs from its services.

What do I need to look out for?

In an ideal world, you would set up your own VPN to create a secure connection through your own home server. But that requires technical skill that only those with a decent amount of experience in IT would attempt. For the average home user, signing up to a reputable VPN service online is probably the best bet.

But not all VPNs are created equally when it comes to privacy. Some keep logs, whether they are compelled to by data retention law or because they use them as a way to sniff out abuses of their system. Others claim to offer anonymity, but track a certain amount of data on users, from the sites they visit to IP addresses. Some VPN providers will also limit traffic for certain services, such as peer-to-peer sharing, and others may not play well with voice-over IP services.

That’s where reading the small print, however dull it may be, will yield some clues.

Pay close attention to logging policies in particular. And it is also worth checking out TorrentFreak’s list of VPN providers that it reviews according to logging policies.

Another thing to consider is protocols. There are a few different types that can be used in VPN, each with their own pros and cons. PPTP, for example, works well with mobile devices and is fast, but Open VPN has stronger encryption. L2T/Ipsec connections are both fast and secure, and while SSTP may have a high level of security, it’s limited in what operating systems it works with.

It stands to reason though that you should choose your VPN carefully. If you have data that you don't want available to everyone, it would be counterproductive to entrust it to a VPN without doing a little research first. Virtual private network: The options There are several options open to you if you want a VPN service. You can go free, but leave yourself open to being bombarded with ads. The paid-for options will also have some extras that could come in handy, whether it's more servers or different protocols. Here's some suggestions:

PRIVATE INTERNET ACCESS Cost: $7 (€6.17) per month or $40 per year. Private Internet Access offers encryption and IP cloaking to users of Windows, Mac, Linux, Android and iOS systems. It also provides local servers in 13 countries, so if you need to access a local server, chances are the company offers it.

STRONGVPN Cost: From $7 per month. Strong VPN starts off cheaply enough but you can pay extra for additional services, such as the ability to change countries, or access different VPN protocols. It has a mind-boggling array of price plans and options though; not for the faint-hearted.

TUNNELBEAR Cost: Free or from $4.99 per month. Tunnelbear is simple and clutter-free, offering users of mobile and laptops the option to browse anonymously. There’s a free service that gives you 500MB of data, with an extra 1GB earned when you tweet about the service. There’s also a paid service that removes that restriction.