Abstract:
The invention comprises a system and method for management of Web users&#39; privacy preferences. In the distributed system, a Web user has a single set of privacy preferences. The single set of privacy preferences and any of its modifications are propagated among Web browsers and Web services. The user&#39;s own privacy preferences are enforced at Web services based on the requester&#39;s privacy policies.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The invention relates generally to Internet based centralized user privacy preferences management technology. More particularly, this invention relates to a system and method for user privacy preferences roaming among clients and Web services and privacy enforcement at Web services base on the requesters&#39; privacy policies. 
     2. Description of the Prior Art 
     The Platform for Privacy Preferences Project (P3P), developed by the World Wide Web Consortium, is emerging as an industry standard providing a simple, automated way for users to gain more control over the use of personal information on Web sites they visit. P3P has been designed to promote privacy and trust on the Web by enabling Web services to disclose their information practices, and enabling Web users to make informed decisions about the collection and use of their personal information. 
     P3P is an important building block of a new privacy protection concept that increasingly focuses on transparency and market-economy elements. At its most basic level, P3P is a standardized set of multiple-choice questions, covering all the major aspects of a Web site&#39;s privacy policies. Taken together, they present a clear snapshot of how a site handles personal information about its users. P3P-enabled Web sites make this information available in a standard, machine-readable format. P3P-enabled browsers can read this snapshot automatically and compare it to the consumer&#39;s own set of privacy preferences. P3P enhances user control by putting privacy policies where users can find them, in a form users can understand, and, most importantly, enables users to act on what they see. 
     P3P allows users&#39; Web browsers to understand Web sites&#39; privacy practices automatically. Privacy policies are embedded in the code of a Web site. Browsers read the policy, and then, automatically provide certain information to specific Web sites based on the preferences set by the users and stored as a User Preference file on the user&#39;s computer. The User Preference file specifies what kinds of practices the user will accept, what kinds should be rejected, and what kinds should cause the program to prompt the user to decide how to respond. 
     The P3P specification provides syntax for specifying privacy policies, privacy preferences (APPEL) and a protocol for exchanging information between the Web site and user agent. Sophisticated preferences may be difficult for end-users to specify, even through well-crafted user interfaces. An organization can create a set of recommended preferences for users. Users who trust that organization can install a pre-defined rule set rather than specifying a new set from scratch. It will be easy to change the active rule set on a single computer, or to carry a rule set to a new computer. 
     Categories are vital to making P3P user agents easier to implement and use; they allow users to express more generalized preferences and rules over the exchange of their data. Categories are often included when defining a new element or when referring to data that the user is prompted to type in, as opposed to data stored in the user data repository. Categories themselves are not data-elements, but are a more generalized description of a set of single data-elements, which belong to this category. 
     Using the policy-reference-file, by defining realms in the header of the answer, servers can not only define different policies on the same server, but also a same policy for different servers. To define different policies on the same server can be useful, when there are pages, that can be browsed and where the service does not collect any data and other pages for shopping or feedback, where data is collected and a certain purpose would be addressed. 
     The first major commercial user agent implementation of P3P is Microsoft&#39;s Internet Explorer 6 Web browser released in the summer of 2001, which is focused on cookie blocking. Other P3P software (for example, the AT&amp;T Privacy Bird) uses the full P3P policy more extensively than it is used in IE6. IBM released a P3P policy editor tool that Web sites can use to create their P3P policies. This tool has been used by many of the Web sites that adopted P3P. 
     After all, only few user agents now support P3P privacy preferences. Even these user agents have implemented only partial solutions such as merely dealing with cookies. These browser based P3P privacy preferences are only applicable when the user is using that particular browser. In addition, because Web services design their access control languages, such as XACML (an XML specification for expressing policies for information access over the Internet) from OASIS and HSDL from Microsoft&#39;s .NET MyServices, Web users are required to manage multiple sets of privacy preferences, each specified in different languages or tools. Further, none of the Web services enforces user&#39;s privacy preferences according to requester&#39;s P3P policies. 
     Therefore, there is a need for a mechanism according to which a user has only a single set of privacy preferences and this single privacy preferences and any of its modifications are propagated among Web browsers and Web services. What is further needed is that the user&#39;s privacy preferences are enforced at Web services based on the requester&#39;s privacy policies. 
     SUMMARY OF THE INVENTION 
     The invention provides a system and method for management of Web users&#39; privacy preferences. In the distributed system, a Web user has a single set of privacy preferences. The single set of privacy preferences and any of its modifications are propagated among Web browsers and Web services. The user&#39;s own privacy preferences are enforced at Web services based on the requester&#39;s privacy policies. The solution gives Web users integrated control over their online privacy relationships and enhances trust between Web service providers and Web users. 
     According to one aspect of the invention, each user has a single set of privacy preferences. A user can make changes of their privacy preferences at either his preferred browsers or services. For example, a user could apply P3P preference editor to create his privacy preferences and then import it into his preferred browser. Alternatively, a user can modify his privacy preferences through permission prompts created by Web services. 
     According to another aspect of the invention, a user&#39;s privacy preferences and their changes are propagated among web browsers and web services.
     1. Propagation from Web Services to Web Browser:   

     When a user signs up a Web service provider (WSP) via a browser without P3P privacy preferences, the WSP offers default privacy preferences to the user, and the user can then make necessary modification on the preferences. The result privacy preferences is sent back to user&#39;s browser as HTTP response. 
     In another situation, after a user replied to a permission prompt whether a Web service consumer site (WSC) could access user data on a WSP, the Web service examines whether the user&#39;s privacy preferences should be changed. If so, the delta of privacy preference changes is propagated from Web services to the Web browser. If the permission message is hosted by the WSP, then the preference changes are sent back from the WSP to the browser via HTTP response header for user&#39;s response. Otherwise, if the permission message is hosted by the WSC, then the preference changes are sent back from the WSP to the browser in two steps: first, SOAP response header is sent from the WSP to the WSC; and second, HTTP response header is sent from the WSC to the browser.
     2. Propagation from Web Browser to Web Services:   

     When a user signs up a Web service via a browser with P3P preferences, the user&#39;s privacy preferences is copied from the browser into the new Web service, and the browser records the URL of this new Web service in its ServicePrivacyURLs file, which consists of the URLs of all Web services which contain a copy of user&#39;s privacy preferences. 
     After a user modified his privacy preferences in a browser, for each URL within the ServicePrivacyURLs file, the user&#39;s modified privacy preferences is propagated from the browser to the corresponding Web services. 
     According to another aspect of the invention, users&#39; privacy preferences are enforced at Web services based on the requester&#39;s P3P policies. Consider a case that a user accesses the Web site WSC, which in turn accesses a Web service WSP. Web service WSP classifies its user data in terms of P3P categories. This can be done via a list of P3P&lt;DATA-STRUCT&gt; elements. The service request from the WSC to the WSP includes p3pReferenceURL, p3 pModificationTime, and userAccessURL. 
     Web service WSP then decides whether it needs to update its local cache of WSC&#39;s P3P policies/references info based on the incoming parameters p3pReferenceURL+p3 pModificationTime. If so, pull WSC&#39;s P3P policies/references information and update local cache appropriately. 
     The WSP then identifies the WSC&#39;s P3P policy used at userAccessURL and evaluate user&#39;s privacy preferences against WSC&#39;s P3P policies to determine whether the service request is allowed or not. 
     If user prompt is needed, the WSP prompts users directly or indirectly via the WSC for permission. Response to this permission prompt can result in the changes of the user&#39;s privacy preferences. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic flow diagram illustrating a method  100  of propagating a user&#39;s privacy preferences from Web services to Web browser; 
         FIG. 2  is a schematic flow diagram illustrating a method  200  of propagating a user&#39;s privacy preferences from a Web browser to Web services; and 
         FIGS. 3A-3C  are schematic diagrams collectively illustrating a method  300  of enforcing a user&#39;s privacy preferences at Web services based on the requester&#39;s P3P policies. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Terminology 
     The following terms shall have the meaning associated therewith for purposes of the discussion herein; 
     Data Element—An individual data entity, such as last name or telephone number. 
     Data Category—A significant attribute of a data element or data set that may be used by a trust engine to determine what type of element is under discussion, such as physical contact information. Categories provide hints to users and user agents as to the intended uses of the data. 
     Data Set—A known grouping of data elements, such as user.home-info.postal. 
     Policy—A collection of one or more privacy statements together with information asserting the identity, URI, assurances, and dispute resolution procedures of the service covered by the policy. 
     Practice—The set of disclosures regarding data usage, including purpose, recipients, and other disclosures. 
     Preference—A rule, or set of rules, that determines what action(s) a user agent will take. A preference might be expressed as a formally defined computable statement such as the APPEL preference exchange language. 
     Service—A program that issues policies and (possibly) data requests. By this definition, a service may be a server (site), a local application, a piece of locally active code, such as an ActiveX control or Java applet, or even another user agent. Typically, however, a service is usually a Web site. In this specification the terms “service” and “Web site” are often used interchangeably. 
     Service Provider (Data Controller, Legal Entity)—The person or legal entity which offers information, products or services from a Web site, collects information, and is responsible for the representations made in a practice statement. 
     SOAP—Simple Object Access Protocol, which provides a way for applications to communicate with each other over the Internet, independent of Platform. SOAP relies on XML to define the format of the information and then adds the necessary HTTP headers to send it. 
     Statement—A P3P statement is a set of privacy practice disclosures relevant to a collection of data elements. 
     URL—Abbreviation of Uniform Resource Locator, the global address of documents and other resources on the World Wide Web. The first part of the address indicates what protocol to use, and the second part specifies the IP address or the domain name where the resource is located. 
     User—An individual (or group of individuals acting as a single entity) on whose behalf a service is accessed and for which personal data exists. P3P policies describe the collection and use of personal data about this individual or group. 
     User Agent—A program whose purpose is to mediate interactions with services on behalf of the user under the user&#39;s preferences. A user may have more than one user agent, and agents need not reside on the user&#39;s desktop, but any agent must be controlled by and act on behalf of only the user. The trust relationship between a user and his agent may be governed by constraints outside of P3P. For instance, an agent may be trusted as a part of the user&#39;s operating system or Web client, or as a part of the terms and conditions of an ISP or privacy proxy. 
     The invention provides a system and method for P3P privacy preferences roaming and enforcement. In this system, each user has a single set of privacy preferences. The user can make changes of his preferences at his preferred browsers or services. For example, a user can apply P3P preference editor to create his privacy preferences and then import it into his preferred browser. Alternatively, the user can modify his privacy preferences through permission prompts created by Web services. 
       FIG. 1  is a schematic flow diagram illustrating a method  100  of propagating a user&#39;s privacy preferences from Web service to Web browser. The method comprises the following steps:
     Step  11   a : The user signs up a WSP  102  via browser  101  without P3P preferences;   Step  11   b : WSP  102  returns “default privacy preferences” to the browser  101 , which then records WSP  102 &#39;s URL in its ServicePrivacyURLs file;   Step  11   c : The user visits a Web Service Consumer (hereinafter as WSC)  103 ;   Step  11   d : If a user prompt is returned from the WSP  102  via WSC  103 , then WSC  103  sends the user&#39;s “permission” to WSP  102 ;   Step  11   e : WSP  102  checks whether the browser  101  needs to be updated;   Step  11   f : It the check result in step  11   e  is yes, then WSP  102  informs WSC  103  to update browser  101  with the “privacy preferences” (SOAP response header from WSP to WSC);   Step  11   g : WSC  103  sends the privacy preference update to the browser  101  (HTTP response header from WSC to the browser);   Step  11   h : If the check result in step  11   e  is no, then WSP  102  acknowledges receiving of the user&#39;s “permission” forwarded by WSC  103 ; and   Step  11   i : WSC  103  replies the user&#39;s HTTP request.   
       FIG. 2  is a schematic flow diagram illustrating a method  200  of propagating a user&#39;s privacy preferences from Web browser to Web services. The method comprises the following steps:
     Step  21   a : The user signs up a Web service provider (WSP)  102  via browser  101  with P3P privacy preferences  104   a;      Step  21   b : WSP  102  requests the “privacy preferences” from the browser  101 ;   Step  21   c : The browser  101  sends a copy of the user&#39;s privacy preferences  104   b  to WSP  102  and records the WSP  102 &#39;s URL in the browser&#39;s ServicePrivacyURLs file which comprises a list of the URLs of these WSPs containing a copy of the “privacy preferences”;   Step  21   d : WSP  102  acknowledges the receiving of the user&#39;s “privacy preferences”;   Step  21   e : The user modifies the “privacy preferences” on the browser  101 ;   Step  21   f : The browser  101  updates all registered WSPs about the updated “privacy preferences”.   
       FIGS. 3A-3C  are schematic diagrams collectively illustrating a method  300  of enforcing a user&#39;s privacy preferences at Web services based on a service requester&#39;s P3P policies. The method comprises the following steps:
     Step  31   a : A user accesses a Web site (WSC)  103 ;   Step  31   b : WSC  103  sends a service request to WSP  102 , the service request including the following data:
       p3pReferenceURL, which is the URL of WSC&#39;s P3P policy reference file;   p3 pModificationTime, which is the latest date/time when WSC modified its P3P policies and/or reference file;   userAccessURL, which is the URL that the user tries to access at WSC.   
       Step  31   c : WSP  102  classifies the user data in terms of P3P categories. This could be done via a list of P3P&lt;DATA-STRUCT&gt; elements. For example:   &lt;p3p: DATA-STRUC Tname=“myProfile.contact.name” structref=“#personname”&gt;&lt;p3p:CATEGORIES&gt;&lt;p3p:physical/&gt;&lt;p3p:demographic/&gt;&lt;/p3p:CATEGORIES&gt;&lt;/p3p:DATA-STRUCT&gt;   Step  31   d : WSP  102  decides whether it needs to update its local cache of WSC&#39;s P3P policies/references information based on the incoming parameters p3pReferenceURL and p3 pModificationTime;   Step  31   e : If the check result in step  31   d  is yes, then WSP  102  pulls WSC&#39;s P3P policies/references information and updates the local cache appropriately, and continues with step  31   f;      Step  31   f : If the check result in step  31   d  is no, then WSP  102  identifies the WSC&#39;s P3P policies used at the userAccessURL;   Step  31   g : WSP  102  evaluates the user&#39;s privacy preferences against WSC&#39;s P3P policies;   Step  31   h : Checks whether the WSC&#39;s P3P policies exclude the user&#39;s privacy policies;   Step  31   i : If the check result in step  31   h  is no, then the service request is allowed and WSP  102  gets data from the database  105  as shown in  FIG. 3B  and replies to WSC  103 ;   Step  31   j : If the check result in step  31   h  is yes, then WSP  102  prompts the user directly or indirectly via WSC  103  for permission;   Step  31   k : Send the user&#39;s preference changes back to the browser via HTTP response header for the user&#39;s response.   
       FIG. 3C  is a flow diagram illustrating the sub-steps of step  31   g  in  FIG. 3A :
     Step  31   l : Identify the set of data fields that WSC is trying to access (for example, by executing XPath parsing);   Step  31   m : Identify the corresponding set of P3P categories by applying the data-to-P3P-category mapping mentioned above; and   Step  31   n : Execute a preference evaluation algorithm by taking input parameters such as (1) WSC P3P policy used at userAccessURL and (2) the set of P3P categories that WSC is trying to access.   
     Although the invention is described herein with reference to the preferred embodiment, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the invention. 
     Accordingly, the invention should only be limited by the claims included below.