Router Password Kracker is a free tool to recover the lost password of your router. It can also be used to recover password from your internet Modem or Web sites which are protected by HTTP BASIC/DIGEST Authentication.
Generally Routers or Modems control their access by using HTTP BASIC or DIGEST authentication mechanism. In simple words, when you connect to your Modem/Router from the browser (typically http://192.168.1.1) you will be asked to enter username & password. If you ever forget this password then you will not be able to access your Router/Modem configuration. Even some websites use this BASIC Authentication to allow only certain users to access their site.