Trimet hop fastpass about farebot

[supersat]

File ID 0 appears to have some ASN.1-encoded data, which is probably an (EC)DSA signature of some sort. After skipping 0x1C bytes and dumping the bytes into openssl's asn1parse:

    0:d=0  hl=2 l=  52 cons: SEQUENCE
    2:d=1  hl=2 l=  24 prim: INTEGER           :3B558AB46FBF8F5B70ED9B47F214800BFB3140F9E05C2E9B
   28:d=1  hl=2 l=  24 prim: INTEGER           :47BAC77B0CEED3E8ADAEFB69609781F447CD90FF34A9FF72
   54:d=0  hl=2 l=   0 prim: EOC

[phcoder]

Can you supply the annotations for this dump or (preferably) another dump with annotations? Like current balance and serial number printed on card

[phcoder]

TLDR: only serial number and issue date is stored on those cards, no balance or trips.

I got my hands on one of those.

• In first 0x1c bytes only the 4 bytes at offset 0xc differ and they correspond to MFG serial number printed on the bottom of the card.
• File 1 contains a const 0x0101 and issue timestamp. Otherwise it's full of zeros.
• The DER blob is also there. Note: it may contain encrypted data with ElGamal rather than a signature but I doubt it since it would mean that the encrypted data is uner 25 bytes and has no signature which is against best practices except if it's some kind of authentication key but this usecase seems also unlikely.
  Presumably it's signature of firsct 0x1c bytes

So it doesn't look like balance is stored on the card. The main serial number may be derivable from MFG number. if it's not the main serial number is unavailable.

[phcoder]

PR: metrodroid/metrodroid#196 . But as I said: almost no info is stored on the card