The communication protocol used by BOLOS to exchange APDU is very close to ISO 7816-4 with a few differences:
Lc
length is always exactly 1 byte- No
Le
field in APDU command - Maximum size of APDU command is 260 bytes: 5 bytes of header + 255 bytes of data
- Maximum size of APDU response is 260 bytes: 258 bytes of response data + 2 bytes of status word
Status words tend to be similar to common APDU responses in the industry.
Field name | Length (bytes) | Description |
---|---|---|
CLA | 1 | Instruction class - indicates the type of command |
INS | 1 | Instruction code - indicates the specific command |
P1 | 1 | Instruction parameter 1 for the command |
P2 | 1 | Instruction parameter 2 for the command |
Lc | 1 | The number of bytes of command data to follow (a value from 0 to 255) |
CData | var | Command data with Lc bytes |
Field name | Length (bytes) | Description |
---|---|---|
RData | var | Reponse data (can be empty) |
SW | 2 | Status word containing command processing status (e.g. 0x9000 for success) |