English:
Well, two weeks ago I read a short description of hacker.org in the c't (a german technology magazine) and registered there. I solved several challenges there and well yeah, once again my interests in cryptology are awakened so I began reading about different cryptographic algorithms. So I grabbed several papers of my digital library and read them, also AVGP gave me a very nice introduction into the different kinds of cryptographic algorithms, the paper's split into four parts. Part three gave me the idea to implement the Vigenère cipher, so I did so. My implementation is not finished, as there are no tests of the key. But I decided to release it now, because it's in a state in what it's functional and easily understandable for people not so good with cryptographic algorithms(Well I'm not that experienced either, but I work on it ). You can get the file here.

Deutsch:
Für diejenigen, die des Englischen nicht sonderlich mächtig sind, fasse ich kurz das wesentliche zusammen:
Ich habe hier eine leichtverständliche, wenn auch nicht wirklich saubere(der Schlüssel wird nicht überprüft) C-Implementierung der Vigenère Verschlüsselung geschrieben, wer sich für Kryptologie interessiert kann sich das ganze ja einfach mal anschauen