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Cosmos App - Ledger Nano S

General structure

The general structure of commands and responses is as follows:

Commands

FieldTypeContentNote
CLAbyte (1)Application Identifier0x55
INSbyte (1)Instruction ID
P1byte (1)Parameter 1
P2byte (1)Parameter 2
Lbyte (1)Bytes in payload
PAYLOADbyte (L)Payload

Response

FieldTypeContentNote
ANSWERbyte (?)Answerdepends on the command
SW1-SW2byte (2)Return codesee list of return codes

Return codes

Return codeDescription
0x6400Execution Error
0x6982Empty buffer
0x6983Output buffer too small
0x6986Command not allowed
0x6D00INS not supported
0x6E00CLA not supported
0x6F00Unknown
0x9000Success

Command definition

GET_VERSION

Command

FieldTypeContentExpected
CLAbyte (1)Application Identifier0x55
INSbyte (1)Instruction ID0x00
P1byte (1)Parameter 1ignored
P2byte (1)Parameter 2ignored
Lbyte (1)Bytes in payload0

Response

FieldTypeContentNote
CLAbyte (1)Test Mode0xFF means test mode is enabled
MAJORbyte (1)Version Major
MINORbyte (1)Version Minor
PATCHbyte (1)Version Patch
LOCKEDbyte (1)Device is locked
SW1-SW2byte (2)Return codesee list of return codes

INS_GET_ADDR_SECP256K1

Command

FieldTypeContentExpected
CLAbyte (1)Application Identifier0x55
INSbyte (1)Instruction ID0x04
P1byte (1)Display address/path on device0x00 No
0x01 Yes
P2byte (1)Parameter 2ignored
Lbyte (1)Bytes in payload(depends)
HRP_LENbyte(1)Bech32 HRP Length1<=HRP_LEN<=83
HRPbyte (HRP_LEN)Bech32 HRP
Path[0]byte (4)Derivation Path Data44
Path[1]byte (4)Derivation Path Data118
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

FieldTypeContentNote
PKbyte (33)Compressed Public Key
ADDRbyte (65)Bech 32 addr
SW1-SW2byte (2)Return codesee list of return codes

SIGN_SECP256K1

Command

FieldTypeContentExpected
CLAbyte (1)Application Identifier0x55
INSbyte (1)Instruction ID0x02
P1byte (1)Payload desc0 = init
1 = add
2 = last
P2byte (1)----not used
Lbyte (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

FieldTypeContentExpected
Path[0]byte (4)Derivation Path Data44
Path[1]byte (4)Derivation Path Data118
Path[2]byte (4)Derivation Path Data?
Path[3]byte (4)Derivation Path Data?
Path[4]byte (4)Derivation Path Data?

Other Chunks/Packets

FieldTypeContentExpected
Messagebytes...Message to Sign

Response

FieldTypeContentNote
SIGbyte (64)Signature
SW1-SW2byte (2)Return codesee list of return codes