https://github.com/nazar-pc/merkle-tree-binary
Set of functions for creating Merkle Tree, proofs and verifying proofs using binary data
https://github.com/nazar-pc/merkle-tree-binary
merkle proof root tree
Last synced: 3 months ago
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Set of functions for creating Merkle Tree, proofs and verifying proofs using binary data
- Host: GitHub
- URL: https://github.com/nazar-pc/merkle-tree-binary
- Owner: nazar-pc
- License: 0bsd
- Created: 2018-05-08T05:22:49.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2023-02-28T21:23:44.000Z (over 2 years ago)
- Last Synced: 2025-04-11T06:14:11.380Z (3 months ago)
- Topics: merkle, proof, root, tree
- Language: TypeScript
- Size: 40 KB
- Stars: 2
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- License: copying.md
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README
# merkle-tree-binary [](https://travis-ci.org/nazar-pc/merkle-tree-binary)
Set of functions for creating Merkle Tree, proofs and verifying proofs using binary data.
This library doesn't hash original data, you have to specify hashes (or binary data of fixed size).
This implementation is vulnerable to a forgery attack ([as a second pre-image attack](https://en.wikipedia.org/wiki/Merkle_tree#Second_preimage_attack)), see these[\[1\]](https://crypto.stackexchange.com/questions/2106/what-is-the-purpose-of-using-different-hash-functions-for-the-leaves-and-interna)[\[2\]](https://crypto.stackexchange.com/questions/43430/what-is-the-reason-to-separate-domains-in-the-internal-hash-algorithm-of-a-merkl/44971#44971) crypto.stackexchange questions for an explanation.
To avoid this vulnerability, you should pre-hash your leaves *using a different hash function* than the function provided such that `H(x) != H'(x)`, alternatively you can record tree depth alongside root hash and check it during validation.
This implementation is vulnerable to a forgery attack ([for an unbalanced Merkle Tree](https://bitcointalk.org/?topic=102395)), wherein, in an unbalanced Merkle Tree, the last leaf node can be duplicated to create an artificial balanced tree, resulting in the same root hash.
To avoid this vulnerability, do not accept unbalanced Merkle Trees in your application.
## How to install
```
npm install merkle-tree-binary
```
## How to use
TypeScript:
```javascript
import {Tree} from 'merkle-tree-binary';
// Do stuff
```
Node.js:
```javascript
var {Tree} = require('merkle-tree-binary')
// Do stuff
```
Browser:
```javascript
requirejs(['merkle-tree-binary'], function ({Tree}) {
// Do stuff
})
```
## API
### merkleTreeBinary.Tree(items : Uint8Array[], hashFunction : (input: Uint8Array) => Uint8Array) : merkleTreeBinary.Tree
Constructor, creates a tree object from items and using specified hash function (items should also be constant-size, like after some hash function).
### merkleTreeBinary.Tree.getRoot() : Uint8Array
Returns `Uint8Array` root of Merkle Tree.
### merkleTreeBinary.getProof(targetItem : Uint8Array) : Uint8Array
Generates a proof for `targetItem` in form of single compact binary string.
Binary string consists of blocks. Each block starts with `0` or `1` for left and right accordingly, where current hash should be inserted and followed by the other hash on the same level.
### merkleTreeBinary.Tree.checkProof(root, proof, targetItem, hashFunction: (input: Uint8Array) => Uint8Array) : boolean
Static function on Tree class, checks whether proof generated by `getProof()` is correct or not.
## Contribution
Feel free to create issues and send pull requests (for big changes create an issue first and link it from the PR), they are highly appreciated!
When reading LiveScript code make sure to configure 1 tab to be 4 spaces (GitHub uses 8 by default), otherwise code might be hard to read.
## License
Zero-Clause BSD
https://opensource.org/licenses/0BSD
https://tldrlegal.com/license/bsd-0-clause-license