# SecureTrie [secure.js:13-16](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/secure.js#L13-L16 "Source code on GitHub") You can create a secure Trie where the keys are automatically hashed using **SHA3** by using `require('merkle-patricia-tree/secure')`. It has the same methods and constuctor as `Trie` # Trie [baseTrie.js:26-57](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L26-L57 "Source code on GitHub") Use `require('merkel-patricia-tree')` for the base interface. In Ethereum applications stick with the Secure Trie Overlay `require('merkel-patricia-tree/secure')`. The API for the raw and the secure interface are about the same **Parameters** - `db` **[Object]** An instance of [levelup](https://github.com/rvagg/node-levelup/) or a compatible API. If the db is `null` or left undefined, then the trie will be stored in memory via [memdown](https://github.com/rvagg/memdown) - `root` **[Buffer or String]** `A hex`String`or`Buffer` for the root of a previously stored trie **Properties** - `root` **Buffer** The current root of the `trie` - `isCheckpoint` **Boolean** determines if you are saving to a checkpoint or directly to the db - `EMPTY_TRIE_ROOT` **Buffer** the Root for an empty trie ## batch [baseTrie.js:710-722](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L710-L722 "Source code on GitHub") The given hash of operations (key additions or deletions) are executed on the DB **Parameters** - `ops` **Array** - `cb` **Function** **Examples** ```javascript var ops = [ { type: 'del', key: 'father' } , { type: 'put', key: 'name', value: 'Yuri Irsenovich Kim' } , { type: 'put', key: 'dob', value: '16 February 1941' } , { type: 'put', key: 'spouse', value: 'Kim Young-sook' } , { type: 'put', key: 'occupation', value: 'Clown' } ] trie.batch(ops) ``` ## checkRoot [baseTrie.js:730-735](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L730-L735 "Source code on GitHub") Checks if a given root exists **Parameters** - `root` **Buffer** - `cb` **Function** ## createReadStream [baseTrie.js:685-687](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L685-L687 "Source code on GitHub") The `data` event is given an `Object` hat has two properties; the `key` and the `value`. Both should be Buffers. Returns **stream.Readable** Returns a [stream](https://nodejs.org/dist/latest-v5.x/docs/api/stream.html#stream_class_stream_readable) of the contents of the `trie` ## del [baseTrie.js:121-139](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L121-L139 "Source code on GitHub") deletes a value given a `key` **Parameters** - `key` **Buffer or String** - `cb` **Function** the callback `Function` ## delRaw [baseTrie.js:211-218](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L211-L218 "Source code on GitHub") Removes a raw value in the underlying db **Parameters** - `key` **Buffer or String** - `cb` **Function** A callback `Function`, which is given the argument `err` - for errors that may have occured ## get [baseTrie.js:65-78](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L65-L78 "Source code on GitHub") Gets a value given a `key` **Parameters** - `key` **Buffer or String** the key to search for - `callback` **Function** A callback `Function` which is given the arguments `err` - for errors that may have occured and `value` - the found value in a `Buffer` or if no value was found `null` ## getRaw [baseTrie.js:147-163](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L147-L163 "Source code on GitHub") Retrieves a raw value in the underlying db **Parameters** - `key` **Buffer** - `cb` **Function** A callback `Function`, which is given the arguments `err` - for errors that may have occured and `value` - the found value in a `Buffer` or if no value was found `null`. ## put [baseTrie.js:87-113](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L87-L113 "Source code on GitHub") Stores a given `value` at the given `key` **Parameters** - `key` **Buffer or String** - `Value` **Buffer or String** - `callback` **Function** A callback `Function` which is given the argument `err` - for errors that may have occured ## putRaw [baseTrie.js:202-202](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L202-L202 "Source code on GitHub") Writes a value directly to the underlining db **Parameters** - `key` **Buffer or String** The key as a `Buffer` or `String` - `value` **Buffer** The value to be stored - `callback` **Function** A callback `Function`, which is given the argument `err` - for errors that may have occured ## checkpoint [checkpoint-interface.js:37-44](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/checkpoint-interface.js#L37-L44 "Source code on GitHub") Creates a checkpoint that can later be reverted to or committed. After this is called, no changes to the trie will be permanently saved until `commit` is called ## commit [checkpoint-interface.js:51-67](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/checkpoint-interface.js#L51-L67 "Source code on GitHub") commits a checkpoint to disk ## revert [checkpoint-interface.js:74-89](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/checkpoint-interface.js#L74-L89 "Source code on GitHub") Reverts the trie to the state it was at when `checkpoint` was first called. **Parameters** - `cb` **Function** the callback ## findPath [baseTrie.js:252-300](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L252-L300 "Source code on GitHub") Trys to find a path to the node for the given key. It returns a `stack` of nodes to the closet node. **Parameters** - `Function` cb - the callback function. Its is given the following arguments- err - any errors encontered - node - the last node found - keyRemainder - the remaining key nibbles not accounted for - stack - an array of nodes that forms the path to node we are searching for - `targetKey` - `cb` # Merkle Proof Static functions for creating/verifying a merkle proof. ## prove [proof.js:12-29](https://github.com/ethereumjs/merkle-patricia-tree/blob/df14ad1fbf861160abdb5954973cf4a570473ce9/proof.js#L12-L29 "Source code on GitHub") Returns a merkle proof for a given key **Parameters** - `trie` **Trie** - `key` **String** - `cb` **Function** A callback `Function` (arguments {Error} `err`, {Array.} `proof`) ## verifyProof [proof.js:39-95](https://github.com/ethereumjs/merkle-patricia-tree/blob/df14ad1fbf861160abdb5954973cf4a570473ce9/proof.js#L39-L95 "Source code on GitHub") Verifies a merkle proof for a given key **Parameters** - `rootHash` **Buffer** - `key` **String** - `proof` **Array<TrieNode>** - `cb` **Function** A callback `Function` (arguments {Error} `err`, {String} `val`) # Internal Util Functions These are not exposed. ## addHexPrefix [trieNode.js:164-179](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/trieNode.js#L164-L179 "Source code on GitHub") **Parameters** - `dataArr` **Array** - `key` - `terminator` Returns **Buffer** returns buffer of encoded data hexPrefix ## asyncFirstSeries [util.js:62-78](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/util.js#L62-L78 "Source code on GitHub") Take a collection of async fns, call the cb on the first to return a truthy value. If all run without a truthy result, return undefined **Parameters** - `array` - `iterator` - `cb` ## callTogether [util.js:36-56](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/util.js#L36-L56 "Source code on GitHub") Take two or more functions and returns a function that will execute all of the given functions **Parameters** - `cb` **Function** the callback ## doKeysMatch [util.js:27-30](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/util.js#L27-L30 "Source code on GitHub") Compare two 'nibble array' keys **Parameters** - `keyA` - `keyB` ## matchingNibbleLength [util.js:16-22](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/util.js#L16-L22 "Source code on GitHub") Returns the number of in order matching nibbles of two give nibble arrayes **Parameters** - `nib1` **Array** - `nib2` **Array** ## _saveStack [baseTrie.js:502-529](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L502-L529 "Source code on GitHub") saves a stack **Parameters** - `key` **Array** the key. Should follow the stack - `stack` **Array** a stack of nodes to the value given by the key - `opStack` **Array** a stack of levelup operations to commit at the end of this funciton - `cb` **Function** ## _updateNode [baseTrie.js:358-423](https://github.com/wanderer/merkle-patricia-tree/blob/dc436426d717fed408f4d46fed23f6d26d03d39d/baseTrie.js#L358-L423 "Source code on GitHub") Updates a node **Parameters** - `key` **Buffer** - `value` **Buffer or String** - `keyRemainder` **Array** - `stack` **Array** - - `cb` **Function** the callback