Merkle Patricia trees provide a cryptographically authenticated data structure that can be used to store all (key, value) bindings, although for the scope of this paper we are restricting keys and values to strings (to remove this restriction, just use any serialization format for other data types). They are fully deterministic, meaning that a Patricia tree with the same (key,value) bindings is guaranteed to be exactly the same down to the last byte and therefore have the same root hash, provide the holy grail of O(log(n)) efficiency for inserts, lookups and deletes, and are much easier to understand and code than more complex comparison-based alternatives like red-black trees.
Understanding the Ethereum Trie
const MerklePatricia = require('@polkajs/merkle-patricia-tree').default;
const MP = new MerklePatricia();
MP.update(Buffer.from('6f3254', 'hex'), 'cat', (err, hash) => {
console.log("HASH1", hash); // 65869c16e2b12917ce52b143349a6faa7e08cb3f8da499aeca619adbe7ffe9db
MP.update(Buffer.from('6f5785', 'hex'), 'dog', (err, hash) => {
console.log("HASH2", hash); // ce79f3b52eb8717a6cfaa1a35acb09ef42acf21be030e3a10c7992f377a24e65
MP.get(Buffer.from('6f5785', 'hex'), (err, value) => {
console.log("value", value); // dog
});
});
});- key: a hex representation of the location within the trie
- cb: (err, value)
- err: if an error it will return a value, otherwise null
- value: a string of the value stored
- payload: input
- return a hex string representation of the hash
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