Opal is the public transport smartcard ticketing system in Sydney, Australia.
Opal cards are MIFARE DESFire EV1 cards, with the application ID 0x314553.
All files are restricted except for file 7, which is freely readable.
The official Android app can interpret this free read data. Much of the information here was derived by reverse engineering this app.
The free read file is 16 octets long.
The data is essentially a 128-bit integer, stored in little-endian. As the fields are not byte-aligned, reading the data as a bitstream is difficult (read: impossible) without reversing the order of the octets.
Offsets and lengths listed are measured in bits, and assume you have reversed the octets. Ranges listed do not include the end bit.
| Start | End | Length | Field description |
|---|---|---|---|
| 0 | 16 | 16 | Checksum |
| 16 | 20 | 4 | Weekly paid journey count |
| 20 | 21 | 1 | Auto top-up enabled |
| 21 | 25 | 4 | Last tap usage type |
| 25 | 28 | 3 | Mode of transport |
| 28 | 39 | 11 | Last tap time: minutes since 00:00 |
| 39 | 54 | 15 | Last tap date: days since epoch |
| 54 | 75 | 21 | Balance in cents (two's complement) |
| 75 | 91 | 16 | Transaction sequence number |
| 91 | 92 | 1 | Card status, 1 if blocked |
| 92 | 96 | 4 | Serial number check digit |
| 96 | 128 | 32 | Serial number |
All card numbers start with the Opal issuer number "308522". This is then concatenated with the serial number zero-padded to 9 digits, followed by the check digit.
The epoch is 1 January 1980 (1980-01-01).
It is believed that tap dates and times are stored in local time (Australia/NSW).
| ID | Description |
|---|---|
| 0 | Rail |
| 1 | Ferry or Light Rail |
| 2 | Bus |
| 3-7 | (reserved) |
| ID | Description |
|---|---|
| 0 | Card has not been used |
| 1 | Tap on: new journey |
| 2 | Tap on: transfer from same mode |
| 3 | Tap on: transfer from different mode |
| 4 | Tap on: Manly-CQ ferry: new journey |
| 5 | Tap on: Manly-CQ ferry: transfer from another ferry 1 |
| 6 | Tap on: Manly-CQ ferry: transfer from different mode |
| 7 | Tap off: distance based fare |
| 8 | Tap off: flat-rate fare |
| 9 | Tap off: automatically completed journey (failure to tap off) |
| 10 | Tap off: end of trip without start (failure to tap on) |
| 11 | Tap off: tap on reversal |
| 12 | Unsuccessful tap (low balance?) |
| 13 | (reserved) |
| 14 | (reserved) |
1 Transfers between ferries can only occur at Circular Quay.
The checksum is a CRC-16-CCITT checksum of the original data (without the checksum). It is stored in big-endian on the card, and is hence little-endian once read in reversed.