password installation

[NumberXIII]

i've had download a file i try to run it, and suddenly this message appears "This installation is password protected. Please enter the password to begin.i don't find a good answers any ideas guys whats the password ???

[Apple]

I suppose it's a a winrar archieve, you must have a password or you can't open the archieve. If even you don't know the password, how would we know..