Unknown file .psar

I recently downloaded a game(resident evil 3) in some console game topic and it contained a eboot.pbp and Keys.bin file.
After some search i found out that .pbp could be opened with phpunpacker.
But now i have more files that I have no idea what to do with it, does anyone know something about those files.
I think it has something to do with PSP but Resident Evil 3 is PS1 game.