Optimistic mining tip (slow block propagation)

The practice commonly referred to as "headers first mining" or "SPV mining" has been identified as a contributing factor to the occurrence of empty blocks in Bitcoin mining. This method presents a risk due to the reliance on the validity of unvalidated incoming blocks, potentially leading to orphaned blocks if these are found invalid. Braidpool proposes a novel solution to this issue by employing a committed mempool that allows for deterministic block templates known to all nodes within Braidpool's network. This system enables often pre-computed templates for incoming blocks, where validation becomes a swift process of comparing the Merkle root. In instances where pre-computation is not possible due to missing parent shares, or "beads," the validation process remains significantly quicker by only necessitating the validation of approximately five transactions instead of the entire block.

Braidpool enhances share relay speed over traditional Bitcoin protocols by utilizing small share sizes and the UDP/QUIC protocol to minimize transmission times. This efficiency allows every Braidpool node to quickly generate and feed the corresponding block to Bitcoin upon recognizing the share. Furthermore, Braidpool contemplates additional optimizations, such as precomputing templates for a second block. This would enable an instantaneous switch to a transaction-filled template if the expected block arrives as a Bitcoin block, thus maximizing miner profits, particularly in scenarios characterized by high fee rates. However, this optimization is limited to blocks mined within Braidpool.

Despite these innovations, the risk of a 51% attack — a concern in decentralized systems where a single entity could gain control of the majority of the network's mining power — remains, albeit shifted towards Braidpool itself. Nevertheless, the system is designed to be safe for universal adoption by miners, suggesting a potential shift in mitigating centralization risks while optimizing mining efficiency and profitability. For more information on the cause of empty blocks being mined, refer to Bitcoin Magazine.