Merkle Patricia Trie

The Merkle-Patricia trie (YP Appendix D): the authenticated radix-16 structure behind the state root, storage roots, and the transaction, receipt, and withdrawal commitments.

• Trie paths and hex-prefix encoding — nibble paths and their compact encoding.
• Ordered trie indices — canonical key order for list-indexed transaction, withdrawal, and receipt tries.
• Trie node types — leaf, extension, and branch forms and their references.
• Trie node codec — canonical hex-prefix/RLP encoding and decoding.
• Trie updates and the canonical builder — sorted update streams and root computation from scratch.
• The witness-native trie — reading and updating a trie through its witness nodes.