Sequence of leafs and internal nodes that where likely by modified after last proof generation

Nodes that may, or may not be mofidied after last proof generation

Returns Some[the current digest of the authenticated data structure], where the digest contains the root hash and the root height Returns None if the proof verification failed at construction or during any of the operations.

The digest consists of the label of the root node followed by its height, expressed as a single (unsigned) byte

Determines if the leaf r contains the key or if r.key < r < r.nextLeafKey If neither of those holds, causes an exception.

Default implementation of error logging.

Figures out whether to go left or right when from node r when searching for the key, using the appropriate bit in the directions bit string from the proof

If operation.key exists in the tree and the operation succeeds, returns Success(Some(v)), where v is the value associated with operation.key before the operation. If operation.key does not exists in the tree and the operation succeeds, returns Success(None). Returns Failure if the operation fails or the proof does not verify. After one failure, all subsequent operations will fail and digest is None.

Deletions go down the tree twice -- once to find the leaf and realize that it needs to be deleted, and the second time to actually perform the deletion. This method will re-create comparison results using directions in the proof and lastRightStep variable. Each time it's called, it will give the next comparison result of key and node.key, where node starts at the root and progresses down the tree according to the comparison results.