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 188ID = C  IDS  A  BWhile in this paper Security Analysis of LMAP++, an RFID Authentication ProtocolID = C  IDS  A  B  IDs  IDs  IDswhere(IDs = PID)Which one is correct?
Which ID extraction is correct?
logic;security
You didn't copy the second equation correctly from the second paper.  The equation in the second paper isIn your notation, this isID =  A  B  C  IDs  IDs  IDsNote: the paper has 3 occurrences of IDs, not 4 occurrences; your post has 4 occurrences.  This makes all the difference in the world.Of course, IDs  IDs  IDs = IDs (follows since X  X = 0 holds for all X).  Therefore, the second equation is equivalent toID =  A  B  C  IDswhich is equivalent to the first equation.Thus, if you accurately copy down the equation from the equation from the second paper, you'll find that it is equivalent to the equation from the first paper.