Home page of Simeon (simos) Xenitellis

Simeon (simos) Xenitellis),
Information Security Group (ISG),
Royal Holloway, University of London,
TW20 0EX Surrey
United Kingdom


  1. What's new?
  2. Contact details
  3. Biography
  4. Main research interests
  5. Publications
  6. Personal interests
  7. Photographic gallery

What's new?

Contact details

Simos Xenitellis,
Information Security Group (ISG),
Royal Holloway, University of London,
TW20 0EX, Surrey
United Kingdom

Mob: +44 (0) 7789 693704
Fax: +44 (0) 7092 280319
e-mail: simoslists@gmail.com, Simos74 at Gmx dot Net, S dot Xenitellis at Myrealbox dot Com, S dot Xenitellis at rhul dot ac dot uk, simos@hellug.gr, simos@teiath.gr


Simeon (simos) Xenitellis (B.Sc. (Athens), M.Sc. (London)) obtained his B.Sc in Informatics in 1998 from the Technological Educational Institute of Athens and his M.Sc. in Information Security from the University of London in 1999.

Main research interests


Personal interests

I am a fan of digital photography and especially the effects you can achieve using the manual mode of the camera. This photo was taken from a park (Saville Gardens) near to the place I study (South England), at 9:00 in the night. I used a tripod and I set the camera for a long exposure shot, duration 15 seconds. Obviously it was pitch black and very difficult to get the camera focus on the subject. Read on to have a look at the photogallery gallery.

The photo of me on the top of this page was taken by one of the professors of the department. While previewing on his digital camera, I said I did not like it and asked to take another one. He did but for some reason he made available the first one. Thus, it's copied here :).

I maintain an online gallery for friends and family (contact me for URL, username/password).

I am the translation leader of the Translation Project (since '98) and the GNOME Translation Project (since '00) for the greek language. I've started the Hellenic Localisation Wiki (Knowledge Base) which is now hosted on ELLAK and continues to evolve as a public Wiki system.

Other OSS (Open Source Software) pet projects are the tcshrc project which maintains a set of configuration files for the tcsh shell (available for most Unix and Windows systems). tcshrc helps in software usability, an important aspect for software engineering.

The XNum project project is a C++ class that performs arbitrary size integer arithmetic. Using the calculation algorithms we learnt at school it can do basic arithmetic. It makes extensive use of overloading (C++ feature) and demonstrates how nicely code can be written in C++. Actually it was written very long ago, in order to calculate the number of 0s at the end of 1000! (one thousand factorial). Actually this problem can be solved with a shortcut; In 1000! one needs to count the number of the 2,5 pairs available, as they produce the zeros at the end of the number. But this is too easy...

Event-driven systems (such as Microsoft Windows) are quite interesting to study. In such a system, different programs communicate with the system through events; if you press A, notepad.exe will receive an event message saying that 'A' has been pressed. In addition, a program can send event messages to other programs, so that they can communicate. In the early days of development of Windows there was no reason to place restrictions as to which program can send what event messages to another program. Thus, nowdays in newer version of Windows where this matters (you can run applications with the credentials of different users on the same session), you can have all this sort of interesting security vulnerabilities.

The Open-source PKI Guide is a document written in 2000 to describe OSS implementations of Public Key Infrastuctures or their components. Unfortunatelly I did not have the time to expand on it and add the recent developments. If someone wants to work on it, I have a work list available. It is written in DocBook SGML; one of the tasks is to convert to DocBook XML :).

If you speak Greek and you are interested in open-source software, have a look at http://planet.ellak.gr/. It's an installation of the http://www.planetplanet.org/ software, localised to Greek.

I maintain a Greek blog at Livejournal and an English one at Advogato.

Photographic gallery

Currently there are 120 photos in the gallery. They have been resized to 800x600 (maximum) for more comfortable navigation. If you would like the full size of a photograph (for example, to set it as background for your desktop), send me an e-mail. The original dimension is 1600x1200.

Last updated: Mon Aug 30 15:55:04 BST 2004