Litecoin Developer Progresses in Adding MWEB Support for Hardware Wallets

Litecoin developer continues to work on Litecoin MWEB support for Hardware Wallets. In November he outlined 5 tasks to start adding MWEB components to the PSBT (Partially-Signed Bitcoin Transaction) format. Litecoin MWEB provides base-layer privacy and also makes litecoin better money as it adds increased fungibility.

Task 1: Add signing logic for inputs and outputs

Task 2: Write the transaction finalization logic

Task 3: Implement component “merging”

Task 4: Add functional test(s) covering the hardware wallet workflow

Task 5: Document the PSBT format additions

In the December update, Burkett focused on continuing his work on PSBT and discovered some limitations in his initial design. To proceed with the PSBT tasks he had outlined previously, he had to redefine many of the MWEB fields. David was able to complete that successfully and has now completed the first 3 tasks.

David also has the basic functional test for the hardware wallet workflow (Task 4), but there are a lot of scenarios he still wants to add tests for. With the PSBT logic coded testing is now in progress.

The code for the PSBT signing logic for inputs and outputs, as well as the component "merging" logic, can be found on the Litecoin GitHub repository.

These include:

Input Signing Logic:

https://github.com/DavidBurkett/litecoin/blob/psbt/src/psbt.cpp#L429

Output Singing Logic:

https://github.com/DavidBurkett/litecoin/blob/psbt/src/psbt.cpp#L409

Component "Merging" Logic:

https://github.com/DavidBurkett/litecoin/blob/psbt/src/psbt.cpp#L527

Overall, Burkett's work will make it possible for Litecoin users to securely store and manage their MWEB funds using hardware wallets such as Ledger and Trezor, allowing for more users to use Litecoin's privacy feature when using cold storage.

Sources:

1. https://litecointalk.io/t/mweb-progress-update-thread-2/53072/17

2. https://twitter.com/DavidBurkett38/status/1600795498755297280?s=20&t=yYXCqKX8JX5oVcOvMLYuww