Cosmos App - Ledger Nano S
The general structure of commands and responses is as follows:
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
Field
Type
Content
Note
ANSWER
byte (?)
Answer
depends on the command
SW1-SW2
byte (2)
Return code
see list of 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
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
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
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
394
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
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
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
394
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
Field
Type
Content
Note
SIG
byte (64)
Signature
SW1-SW2
byte (2)
Return code
see list of return codes