Ethereum's Scalability Bottleneck: Merkle Patricia Trie vs. Verkle Trees

The Ethereum network's Merkle Patricia Trie (MPT) is causing bottlenecks in scalability due to its inefficient design. With current storage requirements of over 150 GB, including all Merkle proofs, and growing at a rate of roughly half that amount every year, the system is becoming increasingly centralized. Only nodes with fast internet connections can process blocks within the 12-second time slot, leaving smaller devices behind.

A potential solution lies in Verkle trees, which use polynomial commitments instead of standard hashes for node computations. This results in a much flatter tree structure and significantly reduced witness sizes. A Verkle tree witness for 1,000 leaves requires only 150 kB, compared to the MPT's 3.5 MB.

The migration to Verkle trees is expected to be complex and will require new data structures, gas accounting models, and cryptography primitives. Developers must also devise a strategy to migrate existing state from the MPT to the VKT without compromising security. The EIP-7864 proposal, which involves using a binary tree design, has been pushed back due to computational costs and quantum risks.