Cosmos App - Ledger Nano S
General structure
The general structure of commands and responses is as follows:
Commands
| Field | Type | Content | Note |
|---|
| CLA | byte (1) | Application Identifier | 0x55 |
| 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 |
Command definition
GET_VERSION
Command
| Field | Type | Content | Expected |
|---|
| CLA | byte (1) | Application Identifier | 0x55 |
| 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 |
|---|
| CLA | 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 | |
| SW1-SW2 | byte (2) | Return code | see list of return codes |
INS_GET_ADDR_SECP256K1
Command
| Field | Type | Content | Expected |
|---|
| CLA | byte (1) | Application Identifier | 0x55 |
| INS | byte (1) | Instruction ID | 0x04 |
| P1 | byte (1) | Display address/path on device | 0x00 No |
| | | 0x01 Yes |
| P2 | byte (1) | Parameter 2 | ignored |
| L | byte (1) | Bytes in payload | (depends) |
| HRP_LEN | byte(1) | Bech32 HRP Length | 1<=HRP_LEN<=83 |
| HRP | byte (HRP_LEN) | Bech32 HRP | |
| Path[0] | byte (4) | Derivation Path Data | 44 |
| Path[1] | byte (4) | Derivation Path Data | 118 |
| Path[2] | byte (4) | Derivation Path Data | ? |
| Path[3] | byte (4) | Derivation Path Data | ? |
| Path[4] | byte (4) | Derivation Path Data | ? |
First three items in the derivation path will be hardened automatically hardened
Response
| Field | Type | Content | Note |
|---|
| PK | byte (33) | Compressed Public Key | |
| ADDR | byte (65) | Bech 32 addr | |
| SW1-SW2 | byte (2) | Return code | see list of return codes |
SIGN_SECP256K1
Command
| Field | Type | Content | Expected |
|---|
| CLA | byte (1) | Application Identifier | 0x55 |
| INS | byte (1) | Instruction ID | 0x02 |
| P1 | byte (1) | Payload desc | 0 = init |
| | | 1 = add |
| | | 2 = last |
| P2 | byte (1) | ---- | not used |
| L | byte (1) | Bytes in payload | (depends) |
The first packet/chunk includes only the derivation path
All other packets/chunks should contain message to sign
First Packet
| Field | Type | Content | Expected |
|---|
| Path[0] | byte (4) | Derivation Path Data | 44 |
| Path[1] | byte (4) | Derivation Path Data | 118 |
| 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 |
|---|
| Message | bytes... | Message to Sign | |
Response
| Field | Type | Content | Note |
|---|
| SIG | byte (64) | Signature | |
| SW1-SW2 | byte (2) | Return code | see list of return codes |
