I saw an interesting article that I think is revelant to this community:
https://medium.com/@kelvinfichter/whats-a-sparse-merkle-tree-acda70aeb837Basically, it's an extention to Merkle tree's so you use the tree as a Key/Value store and allows you to create simple merkel proofs that a value for a specific key doesn't exist. This can help solve double spends, prove censorship etc.
Interestingly enough, the underlying data structure was developed by Google for their certificate transparency effort.
https://www.certificate-transparency.org/.
What I'm trying to understand, is how sparse merkel trees improves upon more traditional authenticated dictionaries. Authenticated dictionaries that use a red/black tree or skip list merkle tree structure that seem to have similar performance. Additionally, proof-of-non-inclusion can be constructred by providing proofs to the left and right of the target key.
Can anyone please enlighten me how sparse merkle trees improve upon more traditional approaches to authenticated dictionaries?
