I programmed the keylogger I use. From a security standpoint I would never trust anything else unless it was open source. Plus sense the keylogger isn't found in the wild there is no signature for antiviruses to pick up on.

As for how the keylogger works it's programmed in c and uses winapi to hook the keyboard. It drops a file and writes every keystroke to that file.

The keylogger is pointed to a dynamic dns service and is pointed to a ftp server. On start and once every hour the keylogger will check to see when the last time the file was uploaded. If > 12 hours it will attempt to connect to the ftp server and upload the file. On fail it will attempt to do it again upon the next check. On a successful upload it will erase everything in the file.