The hathor transaction serialized
| Field | Size (bytes) | Description |
|---|---|---|
version_byte |
1 | Version byte for the transaction apdu protocol |
change_info |
var | Bytes representing the existence of a change output and the bip32 path of the change address |
tx_version |
2 | TX Version, indicates this is a transaction, block, etc. |
num_tokens |
1 | Number of token UIDs present on the data below |
num_inputs |
1 | Number of inputs present on the data below |
num_outputs |
1 | Number of outputs present on the data below |
tokens |
32*num_tokens |
list of Token UIDs |
inputs |
35*num_inputs |
list of Inputs |
outputs |
var | List of Outputs |
Obs: The version_byte indicates how the transaction is serialized, especially the change information.
| Field | Size | Description |
|---|---|---|
num_change_outputs |
1 byte | The number of change outputs on this tx. |
change_output_info |
var | list of change outputs info. |
| Field | Size | Description |
|---|---|---|
change_output_index |
1 byte | the index of the change output |
change_bip32_path_length |
1 byte | The length of the bip32 path |
change bip32 path |
var (4*bip32_path_length) |
an array of 32bit unsigned integers of the path indexes |
Obs: bip32 paths have a hard depth limitation of 5, so the max value of the change output info is 22 bytes.
We don't have to indicate which token this is a change for since the output has that data. We don't validate if there is a max of 1 change per token.
| Field | Size (bytes) | Description |
|---|---|---|
value |
4 or 8 | value of the output, first bit indicates if it's 4 or 8 bytes. If 0: unsigned 32bit integer If 1: value is the negative of the signed 64 bit integer |
token_data |
1 | token data |
script_length |
2 | length of the script |
script |
var (script_length) |
script of the output |
Obs: currently only P2PKH is supported for the script
| Field | Size (bytes) | Description |
|---|---|---|
TX id |
32 | id of the TX the input belongs to |
input index |
1 | output index of the input on the TX being spent |
data length |
2 | length of the data that should follow, but since we are using these bytes as sighash_all, we do not send this data, and this MUST be 0. |
Deterministic ECDSA (RFC 6979) is used to sign transaction on the SECP-256k1 curve.
The SDK call used should be cx_ecdsa_sign of the message.
The message is everything after the change_info (i.e. the sighash_all).
Hathor addresses are generated by b58 encoding the hash160 of the compressed pubkey. For validation, verifying the pubkey hash is enough, but for user confirmation the address must be b58 encoded.