APDU protocol description
This document aims to provide a description of the APDU protocol supported by the app, explaining what each instruction does, the expected parameters and return values
General Structure
The general structure of a reqeuest and response is as follows:
Request / Command
Field | Type | Content | Note |
---|
CLA | byte (1) | Application Identifier | 0xFF, To be determined |
INS | byte (1) | Instruction ID | |
P1 | byte (1) | Parameter 1 | |
P2 | byte (1) | Parameter 2 | |
L | byte (1) | Bytes in payload | |
PAYLOAD | byte (L) | Payload | |
Response
Field | Type | Content | Note |
---|
ANSWER | byte (?) | Answer | depends on the command |
SW1-SW2 | byte (2) | Return code | see list of return codes |
Return codes
Return code | Description |
---|
0x6400 | Execution Error |
0x6982 | Empty buffer |
0x6983 | Output buffer too small |
0x6986 | Command not allowed |
0x6D00 | INS not supported |
0x6E00 | CLA not supported |
0x6F00 | Unknown |
0x9000 | Success |
Commands definitions
GetVersion
This command will return the app version
Command
Field | Type | Content | Expected |
---|
CLA | byte (1) | Application Identifier | |
INS | byte (1) | Instruction ID | 0x00 |
P1 | byte (1) | Parameter 1 | ignored |
P2 | byte (1) | Parameter 2 | ignored |
L | byte (1) | Bytes in payload | 0 |
Response
Field | Type | Content | Note |
---|
TEST | byte (1) | Test Mode | 0xFF means test mode is enabled |
MAJOR | byte (1) | Version Major | |
MINOR | byte (1) | Version Minor | |
PATCH | byte (1) | Version Patch | |
LOCKED | byte (1) | Device is locked | |
TARGET ID | byte (4) | Target ID | |
SW1-SW2 | byte (2) | Return code | see list of return codes |
GetAddress
This command returns the public key corresponding to the secret key found at the given bip32 path, see below.
Command
Field | Type | Content | Expected |
---|
CLA | byte (1) | Application Identifier | |
INS | byte (1) | Instruction ID | 0x01 |
P1 | byte (1) | Request User confirmation | No = 0 |
P2 | byte (1) | ignored | |
L | byte (1) | Bytes in payload | (depends) |
PathN | byte (1) | Number of path components | ? (typically 4) |
Path[0] | byte (4) | Derivation Path Data | 0x80000A55 |
Path[1] | byte (4) | Derivation Path Data | 0xA2862AD3 |
Path[2] | byte (4) | Derivation Path Data | ? |
Path[3] | byte (4) | Derivation Path Data | ? |
Path[4] | byte (4) | Derivation Path Data | ? |
Response
Field | Type | Content | Note |
---|
PK_LEN | byte (1) | Bytes in PKEY | |
PKEY | byte (??) | Public key bytes | |
SW1-SW2 | byte (2) | Return code | see list of return codes |
Sign
This command will return a signature of the passed payload hashed with SHA256
Command
Field | Type | Content | Expected |
---|
CLA | byte (1) | Application Identifier | |
INS | byte (1) | Instruction ID | 0x02 |
P1 | byte (1) | Payload desc | 0 = init |
| | | 1 = add |
| | | 2 = last |
P2 | byte (1) | ignored | |
L | byte (1) | Bytes in payload | (depends) |
The first packet/chunk includes only the derivation path
All other packets/chunks contain data chunks that are described below
First Packet
Field | Type | Content | Expected |
---|
PathN | byte (1) | Number of path components | ? (typically 4) |
Path[0] | byte (4) | Derivation Path Data | 0x80000A55 |
Path[1] | byte (4) | Derivation Path Data | 0xA2862AD3 |
Path[2] | byte (4) | Derivation Path Data | ? |
Path[3] | byte (4) | Derivation Path Data | ? |
Path[4] | byte (4) | Derivation Path Data | ? |
Other Chunks/Packets
Field | Type | Content | Expected |
---|
Data | bytes... | Message | |
Data is defined as:
Field | Type | Content | Expected |
---|
Message | bytes.. | Data to sign | |
Response
Field | Type | Content | Note |
---|
SIG_HASH | byte (32) | Signed hash | SHA256 hash used as signature message |
SIG | byte (65) | Signature | RSV encoded signature |
SW1-SW2 | byte (2) | Return code | see list of return codes |