Abstract
The rapid growth of Ethereum’s world state has created increasing pressure on network efficiency and storage requirements for full nodes. Early ideas such as “state rent,” initially proposed by Vitalik Buterin, suggested periodically charging accounts for occupying space in the world state. However, these concepts were presented at a high level and did not address how to implement such mechanisms efficiently, or how to ensure that removing expired state would not increase the computational complexity of operating the network. Likewise, proposals based on time-based state expiry leave key architectural and performance questions unresolved. This paper presents the first comprehensive, implementation-ready solution that operationalizes the idea of state rent while preserving Ethereum’s current performance guarantees. Our approach, Promethon, integrates periodic charging for stored state with a unified hybrid data structure that combines Red-Black Tree ordering with Merkle-Patricia Trie hashing. This design enables efficient pruning and retrieval without introducing additional time or storage complexity. A pilot implementation in Go demonstrates the practical feasibility of our design and highlights its advantages over prior conceptual proposals.