1. INTRODUCTION The Internet has given the opportunity to share findings and distribute knowledge from experts regardless of time and place. Communication between scientists, institutions, companies, and private persons have adapted to the infrastructure of the Internet. To prevent exposing confidential information high level security policies (HLSP) have been established to guard and protect the confidential data (1). Over the years, technologies, high encryption level software, and data management procedures have been developed and implemented (2) together with firewalls and server protection measurements (3). Unfortunately, one major threat towards confidential data has so far been overlooked. Thus a backdoor to confidential data and information has been left open. 1. Ilioudis C, Pangalos G. A Framework for an Institutional High Level Security Policy for the Processing of Medical Data and their Transmission through the Internet J Med Internet Res. 2001;3(2):e14 2. Albisser AM, Albisser JB, Parker L. Patient Confidentiality, Data Security, and Provider Liabilities in Diabetes Management. DIABETES TECHNOLOGY & THERAPEUTICS 2003;5(4):631-403 3. Norifusa M. Internet security: difficulties and solutions. International Journal of Medical Informatics 1998;49(1):69-74 RESULTS A basic PowerPoint presentation containing 10 slides with few graphical elements have a file size of approximately 50 – 75 kilobits. The same presentation containing an additional graph (Figure 1), pasted as an object linked to the original dataset consisting of more than 120.000 data points, would have a total file size of 150 kilobits. It became clear within hours of researching the problem that many scientists were not aware of the mistakes made. Depending on the topic, up to 5% of the presentation or documents available on the Internet contained objects that were linked to original datasheets. The development on this topic will be monitored and researched further. CONCLUSION Unfortunately, when information based on confidential data is uploaded, a serious and non- intentional mistake may take place. The mistake is made during the production of the document in the following way: Research data are statistically manipulated and made into informative graphs, charts or tables using MS Excel or MS Word. One graph from the spreadsheet application may be copied and pasted into a PowerPoint presentation using the shortcut keys for copy/past (Ctrl + C followed by Ctrl + V). The final presentation is published on the Internet or distributed in the following file formats: PowerPoint Presentation (.PPT), PowerPoint Show (.PPS) or as a Word document (.DOC). Documents converted into the Portable Document Format (PDF) do not contain the metadata and are therefore recommended as file type for distribution. Alternatively the Paste special menu can be found under Edit in the menu bar of PowerPoint applications. By pasting the graph or table into MS PowerPoint or MS Word as a picture the metadata are also excluded. Double click on graph Figure 1 ProcessDataInformationKnowledge Health Informatics Figure 2 Test Graph Download this poster from: www.hi.au.dk Data mining was conducted on the general database Google. The search was restricted to selected areas, using keywords such as: Health, Health Care or Health Informatics. The searching criteria was further restricted using the command: filetype:ppt, filetype:pps or filetype:doc. After downloading a presentation or a document it could be viewed, read or forwarded to colleagues and network partners. Sample files were examined for confidential data or non-intentional linkage of meta data. After opening the file in the relevant application, it was examined for graphs and table content. Slides or pages containing graphs or tables were tested by double clicking the objects. Objects created using the shortcut keys for copy/paste (Ctrl + C followed by Ctrl + V) were hereby identified. METHODS Confidential Meta Data in Presentations and Documents Mads R. Dahl & Søren K. Kjærgaard Section for Health Informatics, Institute of Public Health, University of Aarhus, Denmark University of Aarhus, Health Informatics: WWW.HI.AU.DK E.Mail: MD@HI.AU.DK