Indeed, many authorities exempt dorm rooms from mezuzah. They reason that a student is not considered the “renter” of his particular room since he is paying only for accommodation in general. In fact, the University could move students from room to room, if necessary. Thus, his use of the room is essentially no different than his use of the public rooms or the library. Moreover, even after thirty days, no one would suspect that the student has bought the room from the University! 
According to some authorities, including the Kitzur, the fact that you share this dwelling with a non-Jew is an additional factor to excuse you from affixing a mezuzah.However, I would suggest that, with the University’s permission, you follow the authorities who do require a mezuzah in dormitory situations and those who require on residences shared with non-Jews. You are in a highly challenging environment and need all the spiritual protection you can get! Also, if there are other Jewish students in your dorm, you will be encouraging them to assert their Jewish identity! No berachah is recited on this placement.
 Avnei Nezer Y.D. 380; Shevet HaLevi 2:156. These sources deal with hospital rooms, but are analogous to other dormitory situations.
 Rema Y.D. 286:1; Agur B’Ohalecha 29:7; Chovas HaDar 2:2:6.
 Minchas Chinuch 2:83.
 Bedek HaBayis 286; Aruch HaShulchan 286:2.