What is your opinion about subchains?
A Visual Explanation of Subchains
Subchains are a practical application of "weak blocks," which add security to zero-confirmation transactions and permit massive scaling of Bitcoin.
Fig. 1. Each time a block that satisfies the weak target is found, the subchain is extended. When a block satisfying the strong target is found, the subchain is closed, becoming a strong block, and a new subchain begins.
Fig. 2. Miners cooperate to build subchains in order to process more transactions and claim more fees without incurring additional orphaning risk. This illustration visualizes "idealized" ¼-difficulty subchains (also referred to as 4x subchains). In practice, each strong block may contain more or less than four weak blocks, due to randomness.
Fig. 3. Miners build subchains layer by layer (a – c), where each layer corresponds to the solution of a weak block. To propagate blocks (weak or strong), miners need only send their Δ-block and a reference to the subchain’s tip (f), reducing the quantity of transmitted bytes. When a nonce that satisfies the strong target is found, the subchain is closed thereby becoming a strong block (d), and miners begin working on a new subchain (e).
For further reading, please refer to "Reduce Orphaning Risk and Improve Zero-Confirmation Security With Subchains."
