I'm a Web app (layer seven) hacker. Now that people are starting to do a lot more with XML, I'm seeing a lot of binary formats encoded in Base64, which is such a kludgy encoding scheme that of course spammers were naturally drawn to it to get their garbage past low-end spam filters. It also has useful applications, like encoding a bitmap in a data field and still adhering to the XML schema.
When I wrote this little tool, I was also attempting to get caught up with the latest Microsoft Windows programming paradigm, irritatingly named C#. So this is my first .NET application. Unfortunately, since I refuse to cough up the cash for an IDE, I wrote it in notepad. This means that I didn't have all the drop-down menus that all the programmers whose code I audit have, including the one that lets me create an executable that isn't tied to my machine. What, Microsoft is implementing a security feature?
In any case, if you have a need for a Base64 encoder/decoder that handles binary formats as well as text (which I did, and there were no free tools out there that did it), just compile this code on your own machine and it will make a nice tiny command-line tool to handle it. For the truly lazy, here's the command to do it (you need to download the .NET platform if you don't already have it, of course).
%CSCPATH%\csc.exe /debug- /nologo /t:exe base64.cs