Our modular, high-performance Merkle Tree library for Rust

We've just released rs-merkle-tree, a Merkle tree crate designed with performance and modularity in mind. It comes with the following key features:

* Fixed depth: All proofs have a constant size equal to the depth of the tree. The depth can be configured via a const generic.

* Append-only: Leaves are added sequentially starting from index 0. Once added, a leaf cannot be modified.

* Optimized for Merkle proof retrieval: Intermediate nodes are stored so that proofs can be fetched directly from storage without recomputation, resulting in very fast retrieval times.

* Configurable storage and hash functions: Currently supports Keccak and Poseidon hashers, and in-memory, Sled, RocksDB, and SQLite stores.

The Rust ecosystem already offers several Merkle tree implementations, but rs-merkle-tree is built for a specific use case: append-only data structures such as blockchains, distributed ledgers, audit logs, or certificate transparency logs. It’s particularly optimized for proof retrieval, storing intermediate nodes in a configurable and extensible storage backend so they don’t need to be recomputed when requested.

For those in the know... Do you have any recommended reading for Merkle-curious people that may have some scars from blockchain-related hype? It would be nice to find a nice introductory resource that covers some interesting use-cases that may not be well-known. Perhaps with nice graphics, interactivity, etc.?

For example, here is a slick web site that shows how certificate transparency uses Merkle trees: https://certificate.transparency.dev/howctworks/

There are use-cases outside of "crypto" for blockchain - notably for security related use-cases such as historization ; tough I concede that use-case can be handled with more standard technologies it is very fun to get into it and study such use as it may have properties that could be interesting. One has to have some time for this but to be frank it's not really something super hard to pull-off (Bc itself conceptually)

I think the question, certainly the question I have - is, what are some use cases outside of "crypto" and the CT log ?

You can make use of merkle-trees when ever you want to proof the data integrity of large amounts of individually independent data (distributed FS etc). After playing arround with SMTs for a bit, possible use-cases came to mind quite frequently.