block_graph

BlockGraph: Main Features

• Monotone Structure
  BlockGraph is monotone: once a block is added, it is never removed or modified. The graph only grows, preserving all historical data and supporting append-only semantics.

• Sparse Chain Support
  Blocks can be added at intermittent heights, allowing BlockGraph to represent forks, missing blocks, and partial chains.

• Canonical Tip Selection
  BlockGraph always determines the tip of the "best" (canonical) chain. The canonical tip is selected deterministically based on chain height and block hash, ensuring a unique and consistent view of the active chain.

• Efficient Traversal
  The structure provides efficient iteration over the blocks of the canonical chain (from tip to genesis), enabling fast traversal and inspection of the main chain. Complexity approaches $O(log(n))$ for get and insert operations thanks to the internal skiplist representation.

• Fork and Reorg Handling
  BlockGraph naturally supports forks and chain reorgs, allowing robust handling of blockchain updates and competing branches.

• ChangeSet and Update Application
  BlockGraph can compute and apply changes as a result of "merging" with an updated chain tip, making it easy to synchronize, update, or roll back the chain as needed.

For an explanation of specific design choices see rationale.md.