Opponents such as the ACLU are particularly concerned that the very thing that makes today’s DPI newer and better – the ability to detect at a very granular level exactly what kind of application is being run and treat it according to service provider policy management rules – makes it more dangerous. The major danger lies in the amount of information about consumers that ISPs can collect, Sparapani said.

“The problem here is that when we are building in these capacities, we need to be thinking seriously and prospectively about how this technology can be misused,” he said. “If DPI is built everywhere, will we see the government try to force ISPs or search companies to turn over data or create a back door for the government to execute targeted warrants and requests?”

There are also concerns that data could be used or resold in an inappropriate fashion, he added.

Even the notion of using DPI in combination with technologies such as digital watermarking to detect content theft raises concerns at the ACLU, Sparapani said.

“You are still talking about some sort of government entity policing the Internet and looking for this content,” he said. “Is it going to be the service providers themselves that self-review their traffic? How long will it be before they say, ‘We don’t want the expense of doing this,’ and the government steps in. If we build this technology into the network, the government will want to use it.”

And net neutrality groups such as the Center for Democracy and Technology, whose executive director Alissa Cooper testified at the July hearings, are convinced DPI will primarily be used to give preferential treatment to the ISPs’ own services, to the detriment of competitors.

[Note: This is the second in a three-part series on DPI. The first part can be read here. Coming next: The softer side of DPI.]