Will set the Initial Value, used in conjunction with CBC mode

def setIV(self, IV):
		"""Will set the Initial Value, used in conjunction with CBC mode"""
		if not IV or len(IV) != self.block_size:
			raise ValueError("Invalid Initial Value (IV), must be a multiple of " + str(self.block_size) + " bytes")
		IV = self._guardAgainstUnicode(IV)
		self._iv = IV