Key Value Merkle tree
Merkle tree used in the Sismo ZK-SMPS to build account Merkle trees and world Merkle trees.
This implementation is a classic implementation of Merkle tree with features made for Sismo ZK-SMPS.
Generate your Merkle tree
From data
With the constructor you will be able to instanciate a MerkleTree from MerkleTreeData.
In the default beaviour this will create a tree where the leaves will be hash(key,value).
For example if we take the use case of an airdrop, this could allow you to store the amount of token (the value) associated to a user Ethereum account (the key) in the Merkle tree.
const merkleTree = new KVMerkleTree({
"0xa76f290c490c70f2d816d286efe47fd64a35800a": 1,
"0x0085560b24769daa4ed057f1b2ae40746aa9aab6": 1,
"0x0294350d7cf2c145446358b6461c161a927b3a87": 1,
"0x4f9c798553a207536b79e886b54f169264a7a155": 1,
"0xa1b04c9cbb449d13c4fca9c7e6be1f810e6f35e9": 1,
}, poseidonHash);
Params | Default | Type | Description |
---|
data | null | MerkleTreeData | Data used to generate your Merkle tree. |
hashFunction | null | HashFunction | Hash function used to generate your Merkle tree. |
forceHeight | null | number | Force the number of levels in your Merkle tree. |
hashLeaves | true | boolean | Define if your leaf will be hashed or not. |
The rest of params in the constructor are due to technicals needs, do not add them.
From leaves
const merkleTree = KVMerkleTree.fromLeaves([
"0xa76f290c490c70f2d816da86efe47fd64a35800b",
"0x0085560b24769dacaed057f1b2ae40746aa9aab6",
"0x0294350d7cf2c145446358b64a1c1610927b3a87",
"0x4f9c798553d2075a6b79e886b54f169264a7a155",
"0xa1b04c9cbb449d13c4fc29c7e6be1a810e6f35e9",
...
]);
Params | Default | Type | Description |
---|
leaves | string[] | MerkleTreeData | Leaves used to generate your Merkle tree. |
hashFunction | null | HashFunction | hash function used to generate your Merkle tree. |
forceHeight | null | number | Force the height of your merkle tree. |
hashLeaves | false | boolean | Define if your leaf will be hashed or not. |
Usages
Functions | Description |
---|
getHeight(): number | Return the height of your Merkle tree. |
getRoot(): BigNumber | Return the root of your Merkle tree. |
getValue(key: string): BigNumber | Return the value associated to a key. Not available in a Merkle tree create from leaves. |
getMerklePathFromLeaf(leaf: string): MerklePath | Return MerklePath of a leaf. |
getMerklePathFromKey(key: string): MerklePath | Make the link between key and leaf. This allow you to retrieve the MerklePath without knowing the value associated to a key. Not available in a Merkle tree create from leaves. |
toJson(): JsonMerkleTree | Export your Merkle tree in json format |
KVMerkleTree.fromJson(jsonMerkleTree: JsonMerkleTree): KVMerkleTree | Import your Merkle tree from json format. |
Types
JsonMerkleTree
type JsonMerkleTree = {
root: string,
height: number,
pointers?:
[key: string]: {
leafValue: string,
value: number | null
}
}
tree: {
[nodeValue: string]: {
p?: string,
r?: string,
l?: string
}
}
}
| Description |
---|
root | Merkle root or "top hash" of the Merkle tree (see more) |
height | Number of level of the Merkle tree |
pointers | Key store that allow you to retrieve a leaf from a key without knowing the value. For example in an airdrop, the user will be able to retrieve his leaf from his Ethereum account without knowing the amount of token he deserve |
tree | Merkle tree where p is the parent of the current node, r the right child and l the left child |
MerklePath
interface MerklePath {
path: [BigNumber](https://docs.ethers.io/v5/api/utils/bignumber/)[];
indices: number[]; // 0 if the has is on left, 1 if the has is on the right
}
| Description |
---|
path[] | List of nodes to get the Merkle root from a leaf |
indices[] | 0 if the node is on left, 1 if the node is on the right |
MerkleTreeData
type MerkleTreeData = { [key: string]: number | null };
HashFunction
type HashFunction = (inputs: any[]) => [BigNumber](https://docs.ethers.io/v5/api/utils/bignumber/);}