XIV III
Google
The earliest reference to privacy mode was in May 2005 and used to discuss the privacy features in the Safari browser bundled with Mac OS X Tiger.[2] The feature has since been adopted in other browsers, and led to popularisation of the term in 2008 by mainstream news outlets and computing websites when discussing beta versions of Internet Explorer 8.[3][4][5] However, privacy modes operate as shields because browsers typically do not remove all data from the cache after the session. Plugins, like Silverlight, are able to set cookies that will not be removed after the session. Internet Explorer 8 also contains a feature called InPrivate Subscriptions, an RSS web feed with sites approved for use with InPrivate browsing.[6]
The common web browser plugin Adobe Flash Player began supporting privacy mode in Chrome, Firefox, Internet Explorer, and Safari with the release of version 10.1 in June 2010.[7]
Uses
Privacy mode has multiple uses, including:[8][9][10]
Reducing history, including autofill, browsing, and personal information.
Performing "pure searches" that are not influenced by prior browsing history or networks or friends' recommendations, which may weight and more highly rank certain results than others.
Preventing accidental saving of log-in credentials to accounts.
Signing into multiple accounts simultaneously, via multiple tabs.
Testing websites.
Preventing other users of the computer from finding one's search history.
The Mozilla Foundation performed a study about the user behavior when the feature is switched on and how long the session lasts. The results were that most sessions last only about 10 minutes, though there are periods where activation increases; usually around 11 a.m. to 2 p.m., 5 p.m., between 9 p.m. and 10 p.m., and a minor peak about an hour or two after midnight.[11]
Support in popular browsers
Privacy mode is known by different names in different browsers.
Date Browser Synonym
April 29, 2005 Safari 2.0 Private Browsing
December 11, 2008 Google Chrome 1.0 Incognito
March 19, 2009[12] Internet Explorer 8 InPrivate Browsing
June 30, 2009 Mozilla Firefox 3.5[13] Private Browsing
March 2, 2010 Opera 10.50[14] Private Tab / Private Window
November 18, 2014 Amazon Silk[15] Private Browsing
July 29, 2015 Microsoft Edge InPrivate Browsing
Security
At the year of 2012 Brazilian researchers published the results of a research project [16] where they applied forensic techniques (namely the Foremost data carving tool and Strings program) to extract information about the users browsing activities on IE and Firefox browsers with their private mode enabled. They were able to collect enough data to identify pages visited and even partially reconstruct them.
This research was later extended[17] to include Chrome and Safari browsers. The gathered data proved that browsers private mode implementation are not able to fully hide users browsing activities and that browsers in private mode leave traces of activities in caching structures and files related to the paging process of the operational system.
Another independent security analysis, performed by a group of researchers at Newcastle University in 2014, shows a range of security vulnerabilities in the implementation of the private mode across four major browsers (IE, Firefox, Chrome and Safari).[18] The results are summarized below.
Browser extensions are potential threats to the user privacy. By design, existing browsers (e.g., Firefox, Safari) commonly choose to enable extensions in the private mode by default. This however allows an installed extension to secretly record the visited websites without the user's awareness. Newer versions of Chrome disable extensions in the private mode by default, but allow the private and the normal modes to run in parallel. This makes it possible for an installed extension in the normal mode to learn the user activities in the private mode by measuring the usage of shared computing resources.
