A round of literature from now

This radio service is run by 4 people known

under the codenames River, Royal,

Romulus and Rodent.The service was instrumental in 

bringing out the truth when media failed to.However the 

service could be accessed only by providing the password 

which kept on changing so that no one outside the circle  

knew  about the secret messages and plans.Some of the 

passwords were asfollows-Dearborn,fawkes,meadowsetc.The

following extract is how a broadcast usually ends

"•"Listeners, that brings us to the end of another X. We don't know when it will be possible to broadcast again, but you can be sure we shall be back. Keep twiddling those dials: the next password will be ‘fawkes'. Keep each other safe. Keep faith. Good night."

Ans:Potterwatch