Hierarchical Deterministic Wallet Implementation

[henryyuanheng-wang]

HDWallet that supports generation of private keys, public keys and chain codes for Shelley Address. Changes include:

• poycardano/hdwallet.py: HDWallet class definition and functions, including ingestion of seed, mnemonic words and entropy. Can derive keys based on index or derivation path.

• test/pycardano/test_hdwallet: test and verify address generation from implementation. Test cases are copied from cardano-seriliazation-lib.

• pyproject.toml/poetry.lock: add mnemonic and ecpy dependencies.

[codecov-commenter]

Codecov Report

Base: 85.86% // Head: 85.76% // Decreases project coverage by -0.09% ⚠️

Coverage data is based on head (80b4373) compared to base (919e796).
Patch coverage: 50.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #85      +/-   ##
==========================================
- Coverage   85.86%   85.76%   -0.10%     
==========================================
  Files          22       22              
  Lines        2440     2445       +5     
  Branches      554      555       +1     
==========================================
+ Hits         2095     2097       +2     
- Misses        253      256       +3     
  Partials       92       92              

Impacted Files	Coverage Δ
pycardano/key.py	86.61% <50.00%> (-1.71%)	⬇️

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[robinboening]

Thanks for working on this! I haven't tried your branch, but by looking through the code it looks nice and clean to me 👍

[cffls]

Thanks Henry for raising this PR, this is really amazing! Looks pretty good in general. I added a few minor comments.

One thing to consider is to integrate this with the existing extended public key and signing key in PyCardano. I am thinking about adding a method to_extended_signing_key() in HDWallet. Don't feel the pressure to add it in this PR. We can do it in future PRs.

[cffls]

I guess this is better to be a classmethod?

[henryyuanheng-wang]

Thanks Jerry for taking the time to review! Yeah I was actually thinking of turning those into classmethods. I'll make the modifications.

[cffls]

Same as from_mnemonic, this could be a classmethod.

[cffls]

It may be more intuitive to return a new instance of HDWallet rather than changing the current one and returning self, so people can keep keys derived from different paths at the same time. What do you think?

[henryyuanheng-wang]

This is a a good question. I was thinking of keeping derive_from_path and derive_from_index to have similar behavior - for user to call derive_from_index, they may call the function multiple times, so I was thinking of modifying the keys in place while keeping the extended keys intact. Definitely interested in chatting more on this and figure out the most intuitive implementation :)

[cffls]

Does this support 24 words mnemonic?

[henryyuanheng-wang]

Yep it supports 24 words too and I tested it. I'll add in the test case.

[cffls]

One thing I forgot to mention, sorry.. since HDWallet was initially proposed in bip32, it may be a good idea to move this into the bip32 module here.

[henryyuanheng-wang]

The following changes were made:

• modified from_seed, from_mnemonic and from_entropy to class method
• return child hdwallet instance during derivation instead of overwriting the original hdwallet instance
• added a function to Key so that ExtendedSigningKey can be created from an HDWallet instance. I added function as part of ExtendedSigningKey class instead of a HDWallet class since it resides in bip32 crypto base file. So users should be able to initiate a signing key if they have a valid hdwallet instance. Let me know if this implementation makes sense or if there is a better place to integrate the function with existing code base. Thanks!

[cffls]

LGTM. Thank you Henry for the amazing work!