WIEDER AND GUARNIERI v. THE UNITED KINGDOM JUDGMENT technological development, having been in use since the 1970s, the amount of data that can be carried has steadily risen. Cables carrying data at a rate of 10 gigabits per second were the norm for most of the 1990s. Data rates of 100 gigabits per second have been available since 2010. By 2014 Google had already invested $300million in 60 terabit (60,000 gigabit) per second fibre optic cables. In 2014, it was reported that researchers in the Netherlands and the USA demonstrated data rates of 225 terabits per second.” 33. With regard to the difficulties in attributing online communications, the report stated: “The infrastructure of the internet can make it difficult to attribute communications to their sender and so offers a ‘cloak of anonymity’ for communications. An Internet Protocol [IP] address [IP address] is the identifier for a device on a network. The address may be static or dynamic and is usually written and displayed in the following format: 172.16.254.1 (IPv4 – 32 bits), and 2001:db8:0:1234:0:567:8:1 (IPv6 – 128 bits). IPv6 is the latest version of the Internet Protocol. (a) Dynamic Host Configuration Protocol is used to allocate IP addresses dynamically to devices connected to a network. For example, CSPs assign an IP address to a router and all devices connected to the router use it to form a private IP network. All the connections from the devices on the private network appear to come from the single IP address assigned to the router by using Network Address Translation. CSPs have a pool of IP addresses which are allocated dynamically in sequence, so that a customer’s external IP address will change and different customers will use the same external IP address, but not at the same time. (b) Network Address Translation is a technique used by CSPs to allow a single IP address to be shared by multiple customers simultaneously, sometimes numbered in the thousands. It became necessary due to a shortage of IPv4 addresses, though things will change as IPv6 is increasingly adopted. DRIPA 2014 mandated the retention of subscriber data for some categories of IP addresses, namely, those which are static and those which are dynamically allocated in sequence. The Counter Terrorism and Security Act 2015 [CTSA 2015] seeks to address the difficulty which arises when IP addresses are shared by a number of users simultaneously, by requiring the retention of ‘relevant internet data’ in addition to the shared IP address. However those data are not sufficient to resolve IP addresses in all cases (see 9.51 below); and in any event, a CSP can usually only provide details of the person who pays the internet subscription. This is not necessarily the person who was using a device at a particular time. One problem created by the variety of devices now commonly used was highlighted by submissions to the Review. Smart phones and tablets are often shared by a number of users, such as family members. Each of these users may be accessing different applications. This pattern of usage differs from the traditional use of a mobile phone by one person. In light of this, one service provider suggested that in the future investigations will need to be much more user-specific. IP matching can only help with this to a certain degree. A further problem for the attribution of communications is that an IP address can be changed by the use of a proxy server so that a communication appears to come from somewhere it does not. A proxy server acts as an intermediary between a device and the internet, changing the IP address from that of the actual sender to that of the proxy server. Many use proxy servers for perfectly legitimate reasons, such as to maintain privacy online. However, some use proxy servers in order to carry out cyber attacks so that the origin of the attack remains hidden. Often such attacks involve numerous proxies. 9