Martin Geisler

My name is Martin Geisler, and I am the guy running this website. I am 24 years old and from Denmark, a small country in Northern Europe.

I started studying Computer Science in September 2001 at DAIMI, University of Aarhus but went away to ETH Zürich in Switzerland for a year in 2005/06. Having returned I’m now pursuing a PhD in Cryptography with Ivan Damgård as my advisor.


I’ve worked for Aalborghus Gymnasium (I believe that a gymnasium roughly corresponds to high school in the US.) where I was co-webmaster of their website. The pages are all written in Danish, so it might be a little bit pointless to go and see the pages, unless you should happen to speak Danish, or want to look at the design of the pages which was one of the things I made.

After I started at DAIMI I’ve had the pleasure of being a teaching assistant twice (in the Distributed Systems and Security courses) and a student programmer working on educational materials for the introductional programming course.

Free time

As you can probably tell by now, I enjoy playing with computers. In fact I spend most of my spare time with them. I switched to Linux some time in 1998, and have had a lot of fun with it since. The transparency of the system is the best thing: there’s no stopping you from understanding the system in full detail — except your lack of time :-) I find the [Debian distribution][debian] to be just great.

I’ve received a lot of very positive feedback on a little script I’ve written, called PHP Weather. I must say, that I never imagined that it would grow into what it has become today — thanks everybody! When I think back to when it all started, it’s kind of strange. I just tried to make a script that could parse a METAR — and then it evolved from there. The morale must be this: if you have an idea, then code! Even if you don’t think it’s something big, then suddenly other people discover what you have made, and then it becomes something big.

Another thing which has brought much good feedback with it is my tutorial on PHP. It covers basic PHP and should be good for anybody who doesn’t know much about programming.

If I’m not sitting at my computer or doing homework, then I might be reading or listening to music. I love the Lord of the Rings triology both as books and as films, atmospheric music by Enya, and best of all, spending time with my wonderful girlfriend.

I try to digitally sign my outgoing mail (using this (7E45DD38) GnuPG key) and would of course like incoming mail to be signed and if necessary encrypted. I would be very happy to meet with people for keysigning, just drop me a mail if you happen to be around the Århus area. Send your mail to

You want an image of me? Okay, here ye’ go:

Me on a bike

To answer just a few questions: Yes, that is me riding on a bike and I’m also the photographer. No, I’m not actually doing the paddling, that was done by stunt driver Andreas. Yes, it is actually Mikkel that can be seen trying to catch up with us to the left. And yes, this bike ride was part of our project on random bits in our Cryptography course (it was the “getting there in time for the presentation”-part).


  1. jayu:


    I download this phpshell-2.1 but its not working. When they ask me the authentication. each time give me the error message.

    Jayu shah

  2. Joann:

    I have a website that is coded in PHP. It is a multiplayer game. I am having a lot of problems with this game and I am looking for someone who can lead me in the right direction towards learning some basic PHP. I would like to be able to understand the code so that I can run my site better. Please contact me!!! PLEASE LOL

  3. php programming:

    hello martin.nice to meet you.
    I am Ferdi.
    I Am live in Turkey.

  4. Aputsiaq Niels Janussen:

    Hej Martin, godt at se at siden er oppe og køre igen - jeg ser frem til nye blogindlæg. :-)

  5. Martin Geisler:

    Takker — jeg er holdt lidt op med at blogge og bruger i stedet tiden paa at kode… Jeg er langsomt ved at lave en ny side: Der kommer der nok noget paa et tidspunkt.

  6. Peter Rasmussen:

    Jeg har lavet en artikkel om vikingetidens tårne, du gerne må lægge ud på din side
    Peter, jeg skal bare have en Emailadresse at sende den til

  7. Simon:

    Thank you for a brilliant piece of software. PHP Shell is so convenient and useful!

  8. Andy:

    Thank you for creating PHPShell and making it available to everybody. It’s really very useful. Sadly, I can’t use it anymore since I upgraded my PHP to 5.3. I tried to fix PHPShell myself, but I’m not that good in coding in PHP. Any chance of having PHPShell modified to work also with PHP 5.3?

  9. Martin:

    I am no longer using or developing PHP Shell… You are more than welcome to restart the project :-) Please take a look at the SourceForge page:

  10. John:

    Hey Martin. Like the site. Keep updating with new fresh posts on a regular basis for us return visitors. Happy Holidays.

  11. Martin Geisler:

    Sorry John, but I’ve moved away from blogging. Instead I’m more active on mailinglists and by writing software, especially

  12. Yanbo:

    Hello Martin, fortunately I have found your blog. I’ve tested your PEL project and tried to use it in my project.

    But when I create a new PelJpeg object, I get a PHP warning: Warning: unixtojd() expects parameter 1 to be long, string given in PelEntryAscii.php on line 313, and an other one, Deprecated: Function split() is deprecated in PelEntryAscii.php on line 320.

    I don’t know how to solve this problem, could you help me please. Thanks alot.

  13. MrDog:


    Like Yanbo I have just downloaded the latest PEL source and trying to incorporate into the photo gallery on my website (which currently uses the PHP exif code). But I get the same error as he got (although not the split error)


  14. Martin Geisler:

    Yanbo, Dave: sorry gusy, but I’ve stopped working with PHP and am no longer developing PEL. You should contact the new project admin through the PEL mailinglist, I hope he can help you.

  15. Eleanor Batchelder:

    Thanks, Martin ! Very helpful intro to PHP, just what I needed! (I am already a programmer of other languages…)

    A couple of corrections, if you don’t mind:
    it’s value -> its value
    charecter -> character

    Also, the examples are in a somewhat smaller font size than the rest of the text, so when I zoom to see the examples better, the text is enormous. Maybe you could make them the same size?

    Thanks again,

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