Verizon to allow opt-outs of dubious perma-cookie program, but isn't giving up

Despite criticisms and public outcry, Verizon isn't giving up on its UIDH "perma-cookie" advertising program--but the company will give subscribers a larger say in the matter. Verizon customers will soon have the ability to opt-out of the UIDH program.

"We have begun working to expand the opt-out to include the identifier referred to as the UIDH, and expect that to be available soon," a Verizon spokesperson said via email. The company did not provide a specific date for when the opt-out program would be available.

The UIDH: more than just advertising 

Verizon adds a Unique Identifier Header (UIDH) into every web request a subscriber makes on the company's wireless network. The UIDH--a long string of letters and numbers--is sent in plain text and thus readable by any computer programmed to look for them.

Verizon uses the UIDH to identify a specific device and then deliver advertising to it from the carrier's ad exchange. The company told PCWorld in October that the UIDH is also used for user authentication and fraud prevention. "The UIDH provides a passive validation confirming that the customer is who s/he says," a Verizon spokesperson said via email last fall.

Because Verizon uses the UIDH for more than just advertising, the company does not allow subscribers to opt-out completely. You can stop Verizon from using the UIDH to delivering advertising, but the company will still insert the UIDH for the secondary purposes mentioned above.

Why this matters: The big concern with UIDHs is that other companies would use the public number to track users and create advertising-focused dossiers on them. This turned out to be more than just idle concern when Pro Publica reported that Twitter's advertising exchange MoPub was using the UIDHs for its own purposes. Another advertising firm, Turn, also used Verizon's UIDH, but ceased the practice following public criticism. Given the very real privacy concerns of the UIDH, it's good that Verizon is allowing concerned subscribers to opt-out of the system. It's not a perfect solution, however, as an opt-in program is always preferable to an opt-out one.

Not just Verizon

AT&T was also experimenting with its own take on the UIDH, but the carrier killed its program shortly after Verizon's perma-cookie program went public. AT&T said the perma-cookies were part of a test and that they could return in the future if the company launched a full-scale UIDH-style advertising program.

If AT&T did launch a perma-cookie advertising scheme, it may end up answering some uncomfortable questions put to it by the U.S. Senate. The same day that Verizon announced it would allow customers to opt-out of the UIDH, the Senate's Committee on Commerce, Science, and Transporation (PDF) sent a letter to Verizon CEO Lowell C. McAdam questioning him about the UIDH program.

Protect yourself

Although you can't opt-out of the UIDH program just yet, there are ways to defeat the program. The first way is to stick with Wi-Fi and not Verizon's mobile network whenever possible. When you do need to use the wireless network, ensure that all web traffic is sent using SSL/TLS (HTTPS). Verizon cannot add a UIDH to traffic that is already encrypted. Connecting to the Internet through a virtual private network (VPN) can also defeat the UIDH practice.

Once the opt-out program is active you can test to see if your device still has a UIDH by visiting

[via The New York Times]


Ian Paul

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