I bet the password is going to be her mother's star that was mentioned all the way back in ch2. And then the file is going to have nothing to do with her mother's mathematical thesis and is going to be all about how Furuhashi should follow her dreams.
"1 more try before all the data is erased" I can tell I've spent too much time in the world cyber security when my first thought was "Hmm, windows xp and an old encryption algorithm. Shouldn't be too hard to bypass it."