zeroxcool.net – Harm van Tilborg

Ok, I won’t tell anything about the many updates this log has :).

I’m at the last week school before the fall vacation. It was quite a boring period this semester. Only one class was very useful and fun to follow: cryptography. A course about number theory, symmetric key- and public key cryptography. We had to make a small DES-variant program to encrypt and decrypt text by giving a 16-bit key. We made it in Delphi and it was fun to make!

For public key systems we had to make some exercises in Derive (by Texas Instruments), a math program on the PC. Things of the number theory were examined there. We also had to make some calculations on RSA. For example what if Alice uses a decimal n of 221 and Bob uses an n of 589. We should use a block length of 12-bits and we also use digital signaturing. The message Bob decrypts is not the original one, why? We thought it was because of the fact that (589 / 221) > 2, so that the mod calculations couldn’t fit the length of the blocks. Well, hopefully next time I have the answer, because the exercise is checked about a few days :).

This month we hadn’t much to do at work. I made a new NOC-page which will be available soon. It’s there to let customers see the status of our network and equipment. No kernel updates, no exploitable software holes, no crashing machines, no crashing harddrives, nothing, somebody knows why ;)?

Well, I have to pack my bag for my weekly football training, so speak you soon!