Briefing
The fundamental problem of centralized block construction, exacerbated by Proposer-Builder Separation (PBS) models, introduces a critical censorship risk as builders control transaction inclusion and ordering. This research introduces the Commitment-Inclusion Proof (CIP) mechanism, a foundational breakthrough that allows the block proposer to cryptographically commit to a set of transactions using a succinct proof before the builder finalizes the block. The builder is then mathematically compelled to include only those transactions, effectively decoupling the economic incentive of MEV capture from the liveness and censorship guarantees of the protocol. This new theory establishes a verifiable, trustless layer of transaction inclusion assurance, which is the single most important implication for securing the long-term decentralization of the entire blockchain architecture.
Context
Before this work, the prevailing challenge in high-throughput blockchain design was the inherent conflict between efficiency and fairness, often termed the “MEV trilemma.” Existing PBS models, while mitigating the centralizing pressure on the consensus layer, merely shifted the centralization risk to the block builder, who possesses full discretionary power over transaction ordering and inclusion. This created a theoretical limitation where the protocol’s liveness and censorship resistance were dependent on the builder’s honesty or complex, high-latency auction designs, leaving the system vulnerable to sophisticated front-running and denial-of-service attacks at the block construction layer.
Analysis
The core mechanism is a cryptographic primitive called the Commitment-Inclusion Proof (CIP), which fundamentally differs from previous approaches by separating the commitment to a transaction set from the commitment to the transaction order. Conceptually, the Proposer first uses a Vector Commitment scheme to create a succinct, verifiable commitment to the full set of pending transactions they wish to include. They then generate a zero-knowledge-style proof that this commitment is valid and broadcast it.
The Builder, in the subsequent step, constructs the block and provides a second proof that every transaction in the final block is a member of the Proposer’s original committed set. This two-step, proof-enforced process transforms the builder’s role from a trusted sequencer into a verifiable executor, ensuring inclusion is guaranteed by mathematics, not by economic incentives alone.
Parameters
- Commitment Size – Key Metric ∞ O(log N) where N is the transaction count. (The commitment proof size scales logarithmically with the number of transactions, ensuring constant-time verification for all network participants.)
- Censorship Probability – Security Metric ∞ Approaches 0. (The probability of a builder successfully censoring a transaction committed by the proposer is mathematically negligible, assuming a single honest proposer.)
- Prover Time Complexity – Performance Metric ∞ O(N log N). (The time required for the Proposer to generate the initial commitment and proof scales quasi-linearly with the number of transactions.)
Outlook
This research establishes a new foundational primitive for designing future transaction ordering protocols, opening new avenues for research into provably fair sequencing and MEV-resistant block construction. In the next three to five years, this mechanism will likely be integrated into decentralized sequencers for Layer 2 rollups, enabling a new generation of truly censorship-resistant and fair-ordering execution environments. The theoretical framework also provides a basis for quantifying and proving the censorship resistance of any block production system, shifting the focus of protocol design from mitigation strategies to cryptographic enforcement.
Verdict
The Commitment-Inclusion Proof mechanism provides the foundational cryptographic guarantee necessary to decouple economic incentives from censorship resistance, securing the future decentralization of block production.
