greetings,
class 12th marksheet must be signed by the controller of the examination and the name of the school passed out from is duely mentioned.
the provisional certificate must be signed by the principal of the school.
if the university asks for the principal signature you can get it attested by him/her.
hope this helps.
good luck
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile