Verkle Tree

A tree data structure ('vector commitment' + Merkle tree) that uses polynomial/vector commitments instead of hash branches, producing far smaller proofs (witnesses) than a Merkle Patricia trie when proving many state items at once. Compact witnesses are what make stateless block verification practical, so verkle trees are the enabling cryptography for Ethereum's move toward statelessness. The trade-off is more advanced cryptography than plain hashing.