Allow for non hardened key derivation using BIP32ED25519PublicKey

[eclewlow]

Is your feature request related to a problem? Please describe.
The cardano serialization lib (Javascript) allows for non hardened key derivation using the Bip32PublicKey.
Pycardano only allows HDWallet to derive, and that alone requires a mnemonic or extended private keys.

Describe the solution you'd like
It would be nice if non hardened key derivation could be done using the Bip32PublicKey (which should also be able to be instantiated using an extended public key (64-bytes, as used by the cardano serialization lib - not 78, which some libraries use)

Describe alternatives you've considered
I couldn't find any other libraries that support this. I could open up a subprocess and call Node.js, but I'd rather not.

Additional context
N/A

[cffls]

Thanks for the question. Have you tried the following:

bip_32_public_key = b"...." # this is the 64 bytes pub key
extended_pub_key = ExtendedVerificationKey(bip_32_public_key, key_type="PaymentExtendedVerificationKeyShelley_ed25519_bip32")

Technically it should work without depending on a HDWallet.

[eclewlow]

I would like to do something like this:

public_key = bytes.fromhex("601c86a2310f438079fff07454f4df4ce416bd181d972cd4c4615f15a733ba15")
chain_code = bytes.fromhex("8a34b66a32c9d2d61d1d7a0e8fcf167efae3fb556af74808cd1ba8a22251c031")

hdwallet = pycardano.HDWallet(chain_code=chain_code, root_xprivate_key=None, root_public_key=None, root_chain_code=None, xprivate_key=None, public_key=public_key)

hdwallet = hdwallet.derive(0, private=False, hardened=False)
print(hdwallet.derive(0, private=False, hardened=False).public_key.hex())
print(hdwallet.derive(1, private=False, hardened=False).public_key.hex())
print(hdwallet.derive(2, private=False, hardened=False).public_key.hex())

When running this, at first I get an error

raise ValueError("Missing root keys. Can't do derivation.")

But, if I comment out the following lines, then I get the desired results:

pycardano/pycardano/crypto/bip32.py

Lines 325 to 326 in a9442be

	if not self._root_xprivate_key and not self._root_public_key:
	raise ValueError("Missing root keys. Can't do derivation.")

Now it prints the desired results:

b3f354cbdc2837f823c5e0585995d3bd2d6edf1dc9fc8a1a90d01840c519408d
363aa29a3c93085859310ccddb182abcca18db6f6897a4f936ae82ba0a15af90
db58a4102f555ccb64a0db45259799cbd42fac14f7f6fd1059557fef3961e2c0

Kind of a hack for now, but I feel it should be a feature since non-hardened key derivation should be able to be performed with an extended public key.

[cffls]

Thanks for more details. I think this is doable. Will try to add this feature.