HD Derivation Using Master Key and Chain Code

[HRezaei]

I have this data from another library:

master_private_key_hex = "7c8b1b8348631aa09e98cf4e86858e22c6d8b382d2228df561ded313272ed20c"
master_chain_code_hex = "22938455321020ade51c052afdbb95f6b9c32ee42ec6f979c2de4ef6a605a087"
master_public_key_x_hex = "8fc6455779401f53aa4d54447b8e548b5a4dd5af80b91209f3a3abde74ce7353"
master_public_key_y_hex = "a165346d0f3dd44fd8d97900d00e324f712d926b01f3b0cfebbdbd4dabdaa18c"
path = "0"
child_chain_code_hex = "5cecddb2e7b24c23218a5e79d1943906a7ab838e606af926c30aa78e47769fb7"
child_public_key_x_hex = "189b55e4fd7d5e730999ecef37dc9e021f305b05d23639e83189b01377a600be"
child_public_key_y_hex = "441c5f28ab0268dd497dd7638324673128a94e7e93a29f40a34cd27dd8f8dba3"

And I want to reproduce the same result using hdwallet.
Here I can I create the private key and check its public key coordinates are correct:

from hdwallet import HDWallet
from hdwallet.cryptocurrencies import Bitcoin as Cryptocurrency
from hdwallet.consts import PUBLIC_KEY_TYPES
from hdwallet.hds import BIP49HD, BIP44HD
from hdwallet.derivations import BIP44Derivation, CHANGES
import json

hdwallet: HDWallet = HDWallet(
    cryptocurrency=Cryptocurrency,
    hd=BIP44HD,
    network=Cryptocurrency.NETWORKS.MAINNET,
    public_key_type=PUBLIC_KEY_TYPES.COMPRESSED,
).from_private_key(
    private_key=master_private_key_hex
)

uncompressed_pub_key = hdwallet.public_key(PUBLIC_KEY_TYPES.UNCOMPRESSED)
raw_bytes = bytes.fromhex(uncompressed_pub_key)
x_coord_uncompressed = raw_bytes[1:33].hex()
y_coord_uncompressed = raw_bytes[33:65].hex()

assert(x_coord_uncompressed==master_public_key_x_hex)
assert(y_coord_uncompressed==master_public_key_y_hex)

The above asserts pass successfully. But when I try to test the HD derivation using the code below:

hdwallet.from_derivation(
    derivation=BIP44Derivation(
        coin_type=Cryptocurrency.COIN_TYPE,
        account=0,
        change=CHANGES.EXTERNAL_CHAIN,
        address=0
    )
)

It raises this error:

[/usr/local/lib/python3.12/dist-packages/hdwallet/hds/bip32.py](https://localhost:8080/#) in drive(self, index)
    579             index_bytes: bytes = struct.pack(">L", index)
    580             if not self._root_private_key and not self._root_public_key:
--> 581                 raise DerivationError("You can't drive this master key")
    582             if not self._chain_code:
    583                 raise DerivationError("You can't drive xprivate_key and private_key")

DerivationError: You can't drive this master key

How should I set the root_private_key and root_chain_code? It'd be appreciated if you help me complete the above example, please. A colab notebook is ready here for your convenience.

[meherett]

Derivation requires the chain-code, turn the private key into an extended (x) private key, then proceed to derive.

#!/usr/bin/env python3

from hdwallet import HDWallet
from hdwallet.cryptocurrencies import Bitcoin as Cryptocurrency
from hdwallet.derivations import BIP44Derivation, CHANGES
from hdwallet.consts import PUBLIC_KEY_TYPES
from hdwallet.hds import BIP44HD
from hdwallet.keys import serialize
from hdwallet.utils import integer_to_bytes

master_private_key_hex = "7c8b1b8348631aa09e98cf4e86858e22c6d8b382d2228df561ded313272ed20c"
master_chain_code_hex = "22938455321020ade51c052afdbb95f6b9c32ee42ec6f979c2de4ef6a605a087"
master_xprivate_key_hex = serialize(
    version=integer_to_bytes(
        Cryptocurrency.NETWORKS.MAINNET.XPRIVATE_KEY_VERSIONS.P2PKH
    ),
    depth=0,
    parent_fingerprint="00000000",
    index=0,
    chain_code=master_chain_code_hex,
    key="00" + master_private_key_hex,
    encoded=True
)
master_public_key_x_hex = "8fc6455779401f53aa4d54447b8e548b5a4dd5af80b91209f3a3abde74ce7353"
master_public_key_y_hex = "a165346d0f3dd44fd8d97900d00e324f712d926b01f3b0cfebbdbd4dabdaa18c"
path = "0"
child_chain_code_hex = "03786e91869cb5d09d1613920f331276e05c5469e844acc25620f013a4cb041d9f"
child_public_key_x_hex = "dfad72df0c7d16b9eb1d406fa674e2fabed4c96188d19e55228d1816a36d0b94"
child_public_key_y_hex = "8f7564d215755b1a49cd197c109cc54b1346aad41baba40b75ece2a7cf7319b9"

hdwallet: HDWallet = HDWallet(
    cryptocurrency=Cryptocurrency,
    hd=BIP44HD,
    network=Cryptocurrency.NETWORKS.MAINNET,
    public_key_type=PUBLIC_KEY_TYPES.COMPRESSED,
).from_xprivate_key(
    xprivate_key=master_xprivate_key_hex
)

uncompressed_root_pub_key = hdwallet.root_public_key(PUBLIC_KEY_TYPES.UNCOMPRESSED)
raw_bytes = bytes.fromhex(uncompressed_root_pub_key)
root_x_coord_uncompressed = raw_bytes[1:33].hex()
root_y_coord_uncompressed = raw_bytes[33:65].hex()

assert(hdwallet.root_chain_code()==master_chain_code_hex)
assert(root_x_coord_uncompressed==master_public_key_x_hex)
assert(root_y_coord_uncompressed==master_public_key_y_hex)

hdwallet.from_derivation(
    derivation=BIP44Derivation(
        coin_type=Cryptocurrency.COIN_TYPE,
        account=0,
        change=CHANGES.EXTERNAL_CHAIN,
        address=0
    )
)