This is complicated by the high costs associated with blockchain operations needed for acquiring such liquidity. To address these challenges efficiently and without compromising security or requiring blockchain consensus changes, a construction named SuperScalar has been proposed. This construction leverages laddered timeout-tree-structured Decker-Wattenhofer channel factories with pseudo-Spilman leaves, offering a nuanced approach to handle liquidity provisioning, scalability, and security concerns in a decentralized context.

SuperScalar construction is designed to work within the constraints that ensure security and scalability without necessitating any changes to the Bitcoin blockchain consensus. These constraints include preventing the theft of funds by ensuring an LSP cannot misappropriate funds, making the system resilient against the potential offline status of some end-users, and enabling new users to start with zero Bitcoins. The approach diverges from existing solutions like Ark and BitVM2 bridges by avoiding reliance on a one-honest-member security assumption and managing liquidity in a way that enables independent operation by an LSP without federations.

At the heart of the SuperScalar mechanism are four key components: Decker-Wattenhofer decrementing-nSequence offchain mechanisms, timeout trees, pseudo-Spilman channel factories, and laddering. Each component plays a critical role in ensuring the system's robustness. The Decker-Wattenhofer mechanism allows for consensus on state changes among multiple parties without each change needing to be recorded on the blockchain. Timeout trees enhance the structure by adding a layer that requires everyone's signature, emulating OP_CTV, thus ensuring that funds can be reallocated efficiently and securely even if some users are offline. Pseudo-Spilman channel factories extend this further by facilitating liquidity transfer from the LSP to multiple clients in a unidirectional manner, while laddering introduces financial contract-like flexibility into the investment and liquidity management processes employed by LSPs.

One of the primary advantages of this construction is its ability to provide onchain services on behalf of clients, particularly in terms of unilateral exit, reducing the risk borne by clients due to fluctuating onchain fees. This asymmetric LSP-client scheme not only protects users' funds but also ensures the LSP's incentives are aligned with maintaining the integrity and reliability of the network.

To combat issues like old state poisoning, where an LSP may be tempted to publish outdated states to illegitimately claim funds, the construction incorporates mechanisms that heavily disincentivize such behavior. This includes arrangements where the wrongful publication of an old state would result in the redistribution of funds away from the LSP, effectively penalizing dishonesty.

In addition to technical safeguards, the model also proposes practical considerations for implementation, including incentivizing client onlineness, grouping clients based on activity patterns to optimize liquidity provision, and determining optimal tree structures for managing channels within the network. Moreover, it outlines necessary extensions to existing BOLT specifications to accommodate the complexities introduced by channel factories, suggesting a framework where base node software collaborates with plugins or side-daemons to manage channel factory protocols efficiently.

Overall, the SuperScalar mechanism presents a comprehensive solution to the LSP Last-Mile Problem, balancing the needs for security, scalability, and user-friendliness without straying from the core principles of decentralization and self-sovereignty emphasized by the Bitcoin ecosystem.