Getting round the firewall with a virtual private network

Mainland Chinese get round the firewall by using virtual private networks

Many mainland Chinese use VPNs to obtain information, protect their communications or hide their real identities from internet snoops

China has developed a huge parallel internet sheltered by an electronic firewall known as the Great Firewall of China which blocks, filters and slows traffic on the internet. This significantly obstructs and impacts business, foreign trade and academic, social and cultural exchanges. However, virtual private networks (VPNs) have allowed Chinese web users almost unimpeded access to the internet with the additional benefit of anonymity.

IT professionals there are among the heavy users of VPNs simply because they know how to do it, and because techie sites such as Github are blocked by the firewall, as are chats on Twitter and file sharing on Bittorrent.

Technology companies such as Tencent give all employees full access to the internet. In early 2010 Agence France-Presse reported an estimated 150,000 Twitter users in China. Paradoxically, whereas in the US or Europe one is more likely to hear people say that they can only access Facebook at home because it's censored at work, in China, you are more likely to hear people say, "I can only access Facebook at work" because it's censored at home.

VPNs work by encrypting and anonymising data traffic between computers, so that neither the content, sender or destination of data packets streamed over the net are readable by the firewall. Businesses routinely rely on this resulting anonymity for secure communications, as do hackers for hacking, software pirates for file sharing, porn aficionados for viewing porn, academics for collaborating on Google docs, mass online gamesters for gaming, gamblers for gambling, organised criminals for hiding their identities and dissidents for reading, commenting and "spreading rumours" .

VPN hides your real Internet Protocol (IP) address. If you are in China and connect to a VPN server in another country it substitutes your IP with another IP address from that country, so that you can view online TV, books or other content normally restricted.

If you visit China often you will be concerned about keeping in touch with the world via social media. If you have offices with a broadband connection in the mainland and Hong Kong you can set up a secure VPN between the places.

With the authorities increasingly able to block free wall-jumpers such as freegate, many internet users on the mainland are turning to VPNs, which are also sold on Companies are now offering VPN services for only 15 yuan (HK$19); these are advertised for games players but work like all VPNs.

VPNs are ubiquitous on the mainland. Hackers use VPNs to cover their traces. Academics use them to share documents on Google drive; photographers use them to upload to Picasa; and foreigners use VPNs for Facebook, YouTube, Gmail and Google drive. Many businesses use VPNs to secure their internal communications from eavesdropping by competitors, one reason why the authorities have pulled back from closing down VPNs.

Foreign investors in China are known to be heavy users of VPNs and many might leave if they could not maintain privacy with VPNs. Journalists, too, hide their stories and sources, and some news bureaus might move from Beijing to Tokyo or Hong Kong if their VPNs were pulled.

The beauty of having a VPN service is that you can also use it on your mobile phone and tablet. Both Android and iOS come with built-in VPN support.

Of course, VPNs are not the complete answer to data security. Since the dawn of history, cryptographers and code breakers have been locked in battle, with each advance in encryption soon defeated by the code crackers. So it is probably better to assume that nothing is really secure and can at best only delay decryption of your data. (How long does it take a supercomputer to crunch a tough equation these days?)

If you want data to be really secure, keep it in your head, where it degrades progressively and completely after a few decades.

This article appeared in the South China Morning Post print edition as: Getting round the firewall with a virtual private network