Privacy Enhancing Tools


An Educational Service of the American Library Association

Office for Information Technology Policy


Prepared by Leslie Harris & Associates in conjunction with OITP staff


Another way libraries can protect patron privacy is through the use of privacy enhancing tools.  Just as there are numerous technologies that are used to collect personally identifiable information from patrons accessing the Internet, there are also technologies that can promote privacy online by preventing unauthorized access to communications and stored files, automating the retrieval of information about data collectors' privacy practices, preventing automated data captures through technologies such as cookies and spyware and preventing linkage of communications to a specific individual.  The following is a brief list of some privacy enhancing tools:


+    Encryption is used to protect information stored on a computer or transmitted over the Internet.  Although encryption software is widely available to create secure communications between two computers, this technology is rarely used, largely because most users are unaware of the technology and lack the knowledge to use it.


+    The Platform for Privacy Preferences (P3P) is a standard computer-readable format for online privacy policies developed by the World Wide Web Consortium.  P3P-encoded privacy policies can be automatically retrieved by P3P-enabled browsers and compared with the user-specified privacy settings for automated determination about blocking cookies, preventing web site access, and generating notices.


+    Privacy auditing tools that allow companies to assess whether they are in compliance with their own policies are also emerging, however, these technologies do not have sufficient sophistication to offer a comprehensive audit.


+    Spam filtering software is available to help users limit the amount of spam that they receive.  This software filters the unwanted materials by searching for key words, or blocking mail from particular addresses.


+    Cookie cutters are utility programs that prevent web browsers from exchanging cookies with web sites.  Depending on the program, they may either block all cookies, or allow the user to selectively block certain cookies.


+    Anonymizers are tools and services designed to allow individuals to surf the web or send e-mail anonymously, which helps minimize the risk of linking personal information to a specific identity.


Further information:


Center for Democracy and Technology, Privacy Tools:


EPIC Online Guide to Privacy Tools: 


Considering Consumer Privacy, The Role of Privacy Enhancing



Copyright 2002, American Library Association, Office for

Information Technology Policy




This Online Privacy Tutorial is a service of the American Library Association. The content of this tutorial is primarily the work of Leslie Harris & Associates in Washington, DC. The views expressed in these messages are not necessarily the views of ALA or Leslie Harris & Associates. This tutorial is for information only and will not necessarily provide answers to concerns that arise in any particular situation. This service is not legal advice and does not include many of the technical details arising under certain laws. If you are seeking legal advice to address specific privacy issues, you should consult an attorney licensed to practice in your state.