In lightMAC the message is divided in to M M and so on eg: MM···M[l] ←− M If we consider AES block cipher 128-bit then I am wondering is the size of individual message block is 128-bit as well i,e. M = 128-bit and M= 128-bit ans so on. And why do we need gray code in LightMAC and why is it concatenated with every single message block."If we assume the individual message block is of size 128-bit each, wont there be increase in block size if the gray code is concatinated". Appreciated If anyone can explain this.