Author here.
Bargad is a Trillian like data integrity framework for building efficient blockchains (like Ethereum Plasma does), transparency logs (e.g Certificate Transparency), secure file systems and more.
It Written in Elixir with focus on reliability, concurrency and scalability.
Yesterday I released a paper about Compact Sparse Merkle trees. https://news.ycombinator.com/item?id=18166298.
This framework implements Compact Sparse Merkle trees as well as binary merkle trees to achieve two types of modes: Log and Map mode.