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Crypto.com Chain App

General Structure

The general structure of commands and responses is as follows:

FieldTypeContentNote
CLAbyte (1)Application Identifier0x08
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

These values are based on APDU ISO 7816-4

For a complete list, please refer to pages 59-62 of this document https://www.etsi.org/deliver/etsi_ts/102200_102299/102221/04.00.00_60/ts_102221v040000p.pdf

New API

GET_VERSION

Command

FieldTypeContentExpected
CLAbyte (1)Application Identifier0x08
INSbyte (1)Instruction ID0x00
P1byte (1)Parameter 1ignored
P2byte (1)Parameter 2ignored
Lbyte (1)Bytes in payload0

Response

FieldTypeContentNote
TESTbyte (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 Identifier0x08
INSbyte (1)Instruction ID0x01
P1byte (1)Request User confirmationNo = 0
P2byte (1)Parameter 2ignored
Lbyte (1)Bytes in payload(depends)
Path[0]byte (4)Derivation Path Data0x8000002c
Path[1]byte (4)Derivation Path Data0x8000018a
Path[2]byte (4)Derivation Path Data?
Path[3]byte (4)Derivation Path Data?
Path[4]byte (4)Derivation Path Data?

Response

FieldTypeContentNote
PKbyte (65)Public Key
ADDR_RAW_LENbyte (1)ADDR_RAW Length
ADDR_RAWbyte (??)Address as Raw Bytes
ADDR_HUMAN_LENbyte (1)ADDR_HUMAN Len
ADDR_HUMANbyte (??)Address as String
SW1-SW2byte (2)Return codesee list of return codes

INS_SIGN_SECP256K1

Command

FieldTypeContentExpected
CLAbyte (1)Application Identifier0x08
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 contain data chunks that are described below

First Packet

FieldTypeContentExpected
Path[0]byte (4)Derivation Path Data0x8000002c
Path[1]byte (4)Derivation Path Data0x8000018a
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
Databytes...Message

Data is defined as:

FieldTypeContentExpected
Messagebytes..Data to sign

Response

FieldTypeContentNote
secp256k1 Rbyte (32)Signature
secp256k1 Sbyte (32)Signature
secp256k1 Vbyte (1)Signature
SIGbyte (variable)SignatureDER format
SW1-SW2byte (2)Return codesee list of return codes