I was up on campus again for my 5 year reunion, and it felt wrong to not be doing something slightly sketch around the Dartmouth ID, just for old time's sake. Luckily, I'd recently acquired a Flipper Zero for some exploration around the old Gamebody Link Cables which allowed me to put some of my historical information to the test.
I wrote originally about the Dartmouth ID's RFID capabilities citing a 2005 article. The relevant piece was
Dartmouth ID cards are DuoProx-model cards manufactured by HID.
which I then explored in my followup post about mimicking the cards. I went back and forth on the type of card, which is now experimentally answerable!
Scanning my Dartmouth '18 ID reveals that it IS
HIDProx and 125kHZ. Now that I'm 5 years out of school there's no need to censor my data, so here it is directly.
02 A1 C2 35 09 90
35-bit HID Proximity
This is a little interesting because the 2005 article states that "the only information stored on the RFIDs in student ID cards is the account number printed on the lower right backside of the cards." However, this data doesn't match any of the numbers on the card: my Dash ID, my Hinman box # (2331001088892), or the account number printed on the back of my card (964235D 108620).
While I was there, I also scanned the ID of a current '24. They're still on campus, but I can provide a slightly anonymized version of their RFID data. You can see that some of the leading information is only slightly different (A1 -> C1, 35 -> 55) while as the remaining X data is all different. Ideally I would have the account number as well to serve as another data point, but I only have the scan.
02 C1 C2 55 XX XX
As to the efficacy of Flipper, it worked perfectly. Emulation acted as if I was using the card itself. I could even write the newer data to my old Dartmouth ID, and it scanned correctly into multiple buildings that my alumni badge no longer had access to. All in all, a fun and useful toy for a weekend.