Richard Clayton's Analysis

On Wednesday 26th March 2008 Richard Clayton of the Foundation for Information Policy Research had a wide-ranging technical briefing from Phorm. Following this he produced a report on 4th April, The Phorm "Webwise" System, subsequently revised on 23rd April and 18th May. This set out fully how Phorm was expected to work at that time.

His meeting with Phorm did not reassure him:
"Overall, I learnt nothing about the Phorm system that caused me to change my view that the system performs illegal interception as defined by s1 of the Regulation of Investigatory Powers Act 2000."

Diagrams

Subsequently diagrams based on his report were published on picasaweb showing:
How a request for a web page is fulfilled without Phorm, based on its design at the time
How a request for a web page is fulfilled if Phorm is present, based on its design at the time.

Deep Packet Inspection

However Phorm works, it will need to use a technique called Deep Packet Inspection.

Wikipedia's entry on Deep Packet Inspection says:
"Deep packet inspection (and filtering) enables advanced security functions as well as internet data mining, eavesdropping, censorship, etc. Advocates of net neutrality fear that DPI technology will be used to privatize the Internet."