Microsoft's privacy protection feature in Internet Explorer, known as P3P, is impractical to comply with while providing modern web functionality such as cookie-based features, Google said Monday in response to an accusation from Microsoft that Google had bypassed privacy protections in Internet Explorer.
Google is already facing allegations that the company circumvented privacy settings in Apple's Safari browser to plant cookies on users.
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"We've found that Google bypasses the P3P Privacy Protection feature in IE," Dean Hachamovitch, Microsoft's corporate vice president for Internet Explorer said in a blog post. The result is similar to the recent reports of Google's circumvention of privacy protections in Safari, even though the actual bypass mechanism Google uses is different, he added.
IE by default blocks third-party cookies unless a site presents to the browser a P3P Compact Policy Statement describing how the site will use the cookie and pledging not to track the user. Third party cookies are those dropped by domains other than the one in the user's browser address bar.
Google sends a P3P policy that fails to inform the browser about Google's use of cookies and user information, and is in fact a text statement that it is not a P3P policy, Hachamovitch said. The company is taking advantage of a technical nuance in the P3P specification, as in an attempt to leave room for future advances in privacy policies, the P3P specification states that browsers should ignore any undefined policies they encounter, he said. "P3P-compliant browsers interpret Google's policy as indicating that the cookie will not be used for any tracking purpose or any purpose at all," Hachamovitch said.
Google's senior vice president of communications and policy, Rachel Whetstone, countered in an emailed statement that Microsoft's policy is "widely non-operational".
Newer cookie-based features are broken by the Microsoft implementation in IE, Google said. These include features such as Facebook "Like" buttons, the ability to sign-in to websites using a Google account, and hundreds more modern web services. It is well known that it is impractical to comply with Microsoft's request while providing this web functionality, Google added.
Google said it has been open about its approach on P3P, and so have other websites including Facebook.
The cookies Google uses to secure and authenticate an user's Google account, and store his preferences, may be served from a different domain than the website the user is visiting, Google said on its support site. "The P3P protocol was not designed with situations like these in mind. As a result, we've inserted a link into our cookies that directs users to a page where they can learn more about the privacy practices associated with these cookies," it added.
Whetstone also referenced a Facebook statement on its website, that the P3P standard is now out of date and does not reflect technologies that are currently in use on the web, so most websites currently do not have P3P policies. "The organization that established P3P, the World Wide Web Consortium, suspended its work on this standard several years ago because most modern web browsers do not fully support P3P," it added.
Facebook social plugins are built and designed to protect privacy by providing users with social experiences on other websites without requiring any additional cookies to be set, the company said in a statement. "Therefore, our P3P policy is not intended to enable us to set additional cookies or to track users," it added.
Lorrie Faith Cranor, an associate professor of computer science and of engineering and public policy at Carnegie Mellon University, said in a blog post last week that companies sometimes use invalid CPs (compact policies) to circumvent Internet Explorer cookie blocking. CPs include codes that summarize the privacy policy for the cookie. A 2010 study by researchers from Carnegie Mellon collected CPs from 33,139 websites and detected errors in 11,176 of them, including websites of Facebook and Microsoft.
Facebook said that P3P, which was developed many years ago, is not effective in describing the practices of a modern social networking service and platform. Facebook has instead posted a public notice describing its practices which is consistent with Section 3.2 relating to policies in the P3P specification, it said.
The section of the P3P 1.0 specification states that in cases where the P3P vocabulary is not precise enough to describe a website's practices, sites should use the vocabulary terms that most closely match their practices, and provide further explanation in a human-readable consequence field or policy.
Google said last week that it did not intentionally install tracking cookies in response to a report about alleged privacy violations of Safari users. "We used known Safari functionality to provide features that signed-in Google users had enabled," Whetstone said in a statement last week. "It's important to stress that these advertising cookies do not collect personal information."
Three lawmakers from the U.S. House of Representatives have asked the Federal Trade Commission to investigate if the allegations of privacy violations of Safari users by Google is in violation of a consent agreement the company reached with the FTC last year.
[Nancy Gohring in Seattle contributed to this report.]
John Ribeiro covers outsourcing and general technology breaking news from India for The IDG News Service. Follow John on Twitter at @Johnribeiro. John's email address is john_ribeiro@idg.com