Leading zeros in ExtendedPrivateKey break PrivateKey

[l0rb]

When creating a PrivateKey from the output of serialize_key() on ExtendedPrivateKey the leading zeros that this data has break the pub() function on the PrivateKey. Code example below:

rootkey = 'tprv8....'

# this throws an error
PrivateKey(
    ExtendedPrivateKey.decode(rootkey).serialize_key()
).pub()

# this one works
PrivateKey(
    ExtendedPrivateKey.decode(rootkey).key.serialize()
).pub()

[SimoneBronzini]

Looking into it right now

[SimoneBronzini]

The serialize_key method is not intended to create regular keys from extended keys. It is defined in the ExtendedKey abstract class so that child classes have to implement a method which serialises them in the format expected by extended serialisation. serialize_key() should probably be made private. What you are trying to achieve is supposed to be done as follows:

ExtendedPrivateKey.decode(rootkey).pub()  # this returns the corresponding ExtendedPublicKey
ExtendedPrivateKey.decode(rootkey).pub().key  # this returns the corresponding PublicKey

[l0rb]

I see. Tanks for the prompt response and clarification!

[SimoneBronzini]

Made serialize_key() and serialized_public() private in 2729f24.