Litecoin MimbleWimble June Update

Good news/bad news everyone! We’re officially halfway through 2020, and now that we’re past June, David Burkett, the project lead for the Litecoin MimbleWimble implementation, has released another development update, so let’s get started.

We start with the mempool logic. Burkett said further investigation had proven this area to be ‘significantly more complex’ than expected, so a review would be needed following the testnet launch this September.

“But now a minimal implementation that supports MW transactions has been written.”

Additionally, code has been written to support extended block mining to store MimbleWimble transactions. ‘There remain a few edge cases to deal with and much more testing is needed,’ reports Burkett. However, as Burkett writes, this update raises some concerns.

“I had concerns about how mimblewimble block data was stored in a separate database. It was originally designed this way to be completely decoupled from existing code to facilitate merging of future Bitcoin commits. But having a separate database is generally a bad idea. This is because you lose the ability to update atomically and the two databases may become out of sync. “This can cause numerous issues and could potentially be exploited by remote attackers.”

Due to these concerns, Burkett ‘decided to invest time modifying the code for serializing and deserializing MW blocks and transactions to disk’.

“By leveraging the foundation we laid as part of our Segwit improvements, we were able to cleanly support additional data serialization without requiring major changes to our existing block storage format. As a result, upgraded nodes can successfully store extended block data to disk in the same location where they have always stored the blocks, without the need to introduce an additional database. A side effect of this change is that it is relatively straightforward to add support for sharing mimblewimble transactions over a p2p network, a first step toward our July goal of processing MW data as part of the initial block download.”

Future Development The MimbleWimble roadmap has now been updated and is well underway with a focus on initial block downloads in July, chain reconfiguration logic in August, and activation logic and testnet launch in September.

David Burkett is a publicly funded developer working on the Litecoin Core Project.