This question related to attack on the LMAP++ the result of extracting ID from the messages. In Passive Attack on RFID LMAP++ Authentication Protocolm, page 188
ID = C ⊕ IDS ⊕ A ⊕ B
While in this paper Security Analysis of LMAP++, an RFID Authentication Protocol
ID = C ⊕ IDS ⊕ A ⊕ B ⊕ IDs ⊕ IDs ⊕ IDs
where(IDs = PID)
Which one is correct?