Clique is a modification of the Elgg social networking platform. Clique provides users with a social network platform that enables them to keep control over their privacy. This includes, for example, fine grained access control and configuration of multiple faces (e.g. family, personal, professional) that can be used for interactions with other users. When posting a data item, e.g., name, birthday or profile photo on the site, the user can define for every single other user whether they should be able to see it or not.

License Programming Language Operating System/Platform Category Intended Audience Download
GPLv2 PHP PHP/MYSQL/Apache with mod_rewrite, GD,JSON, XML, Multibyte String support Social Network end-users tgz, Live Demo

Feature list:

  • collections – contacts are organised in collections, roughly corresponding with social circles. Users can form different instances by defining close friends, family, colleagues, former school-friends,….
  • flexible access control to content – all content contains attribute certificate policies based on moving collections and contacts in a plain and easy to use graphical user interface
  • visual audience indicators – all content is labeled by icons showing who has access to the information
  • fading relations – depending on the activity of one’s contacts, these users slowly disappear. At first this happens through visual indicators (coloured border around user icon), later by closing access to one’s data from the automatically defriended contact.

How to Use

The Clique demonstrator can be accessed through

The library comprises only the implementations of the credential system features, additional required components for building various kinds of practical systems are not included in the library. An example for such a component is an access control system that you might want to use in conjunction with the Identity Mixer (LINK) system. PrimeLife is building a policy engine which is capable of expressing semantics of anonymous credential systems. A first version based on the PRIME policy engine is already available. Identity Mixer has been integrated into the PRIME Core as one example use case within a comprehensive privacy-enhancing identity management system.

Target Audience

Who may be interested in the component?

  •     The general public
  •     Providers of private social networks
  •     Privacy-savvy developers

Future Plans

We plan to extend Clique with more features. Clique is currently in a public evaluation phase. The system is live since January 2010 and experiments and questionnaires will be conducted with actual users of the system. The results of these studies will be used to improve the system and devise new functionality.

More information: Future Plans for the next year

Further Information


Size: 2,09 MB


Platform: Elgg (, a PHP/MYSQL/Apache based open social networking site platform. The basic software Elgg runs on a combination of the Apache web server, MySQL database system and the PHP interpreted scripting language. This is one of the most popular web server environments. Due to Elgg’s advanced functionality, there are some extra configuration requirements that are explained in the following.

  • The Apache web server needs to be installed with the following modules:

    • mod_rewrite
    • PHP5
  • MySQL 5+ is needed for data storage PHP 5.2+ needs to be installed as an Apache module (not in CGI mode or safe mode) with the following libraries:
  • GD (for graphics processing, e.g. user icon rescaling and Captcha)
  • JSON (for API functionality)
  • XML (not installed/compiled by default on all systems)
  • Multibyte String support (for internationalisation)

It is recommended that you increase the memory available to PHP threads beyond the standard 8 or 12MB, and increase the maximum uploaded filesize (which defaults to 2MB). By default, these settings have been set for you in the .htaccess file in the base Elgg directory.

Architecture: Apache, PHP, MySQL.


License: Clique is licensed under GPLv2. The text of the license is available at


Documentation: Available at



  • PrimeLife D1.2.1, D1.2.2 Ronald Leenes – Context is everything, sociality and privacy in online Social Network Sites, to appear in Simone Fischer-Hübner, Marit Hansen, etc (eds), PrimeLife/IFIP Summerschool 2009.


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Last update: March 2010