An encryption mechanism used on cooperative multi-band wireless STA architecture that enables full duplex operations. In encrypting a frame, an AAD can be constructed by using a selected MAC address, which may not be associated with a band to be used for transmitting the frame in an upcoming TXOP. An STA that supports simultaneous transmission in a multi-band operation uses the same MAC address to encrypt the frames to be transmitted on different bands. An AAD is constructed by using a same MAC address corresponding to one of the transceivers. A transmit STA may specify band information used for encryption in the MAC header, which serves to signal the receive STA to decrypt the frame by using the proper information.