Delete comment from: Ken Shirriff's blog

Ken Shirriff said...

One random thing I just noticed about the Montreal tickets. The 15-digit number on the back of the ticket is the serial number of the RFID chip, converted from hex to decimal and prefixed with "01-". Specifically, it is UID6 through UID1 (excluding UID0).

And on the Washington DC metro card, the 20-digit number on the card matches the serial number of the RFID chip if you remove the first 4 digits (0167) and the last digit (check digit?). Specifically, it is UID1 through UID6, the reverse order compared to Montreal. Little-endian vs big-endian!

Jul 13, 2024, 3:49:46 PM

Posted to Inside the tiny chip that powers Montreal subway tickets