A Virtual Private Network, abbreviated as VPN, makes it possible to build secure private connections over public access network infrastructures. Today VPNs are usually based on Internet Protocol (IP) and use the public Internet to establish the connection. Depending on the type and use, a VPN can be created between two terminals (computers), between a computer and a network or between two networks. In the latter case, the VPN connection of two routers is realised. The data transmitted within a VPN is encrypted and protected against unauthorised access in a sort of tunnel through the Internet. Encryption standards such as IPSec or TLS/SSL are used. Many private Internet routers now have VPN functionality and allow laptops, smart phones or tablets that are being used elsewhere to create a secure connection to the home network. This technology makes it possible, for example, to protect data transmitted to and from a public hotspot to a home network and to access the Internet from there.