Certain aspects of the present disclosure provide a method for wireless communications by a transmitter user equipment (UE). The transmitter UE generates a message authentication code, based on information within a sidelink master information block (SL-MIB) and a key shared between the transmitter UE and a receiver UE. The transmitter UE transmits a sidelink broadcast channel (SL-BCH) transmission carrying the SL-MIB and the message authentication code.