nmmr
Version:
Merkle Mountain Ranges as used on the Nostr protocol
100 lines (84 loc) • 2.96 kB
Markdown
This is a [fork](https://github.com/HerodotusDev/merkle-mountain-ranges) from Herodotus Dev Ltd's merkle-mountain-ranges npm package
altered to fit Nostr protocol ecosystem
```sh
$> npm i nmmr
```
```js
import NMMR from 'nmmr'
// Append data as bytes then save chunks to nostr event
const t = new TextEncoder()
const nmmr = new NMMR()
await nmmr.append(t.encode('a'))
await nmmr.append(t.encode('b'))
const expectedRoot = nmmr.getRoot()
const chunks = []
for await (const chunk of nmmr.getChunks()) {
// chunk = { contentBytes, index, total, proof }
chunks.push(chunk)
await createAndPublishNostrEvent(chunk)
}
// Later verify some chunk is really part of the whole
const chunk = chunks[0]
NMMR.verifyProof({ ...chunk, root: expectedRoot })
// Or derive the root when it is supplied by another signed object.
const root = NMMR.calculateRoot({
contentBytes: chunk.contentBytes,
index: chunk.index,
total: chunk.total,
proof: chunk.proof
})
```
Version 2 hashes each leaf as
`sha256(uint(nodeIndex) || sha256(contentBytes))`. Proofs are a compact
`Uint8Array` containing 32-byte sibling hashes followed by the other MMR peaks.
The target leaf and root are not repeated in the proof.
Note: Prefer using the above default export.
```js
import { InMemoryMMR } from 'nmmr'
const mmr = new InMemoryMMR()
const leaves = 11 // Total node size will be 19
for (let idx = 0; idx < leaves; ++idx) {
await mmr.append((idx + 1).toString()) // Leaf number starts at 1 in this implementation.
}
/*
Height
3 15
/ \
/ \
/ \
/ \
2 7 14
/ \ / \
1 3 6 10 13 18
/ \ / \ / \ / \ / \
0 1 2 4 5 8 9 11 12 16 17 19
*/
// Generating a proof for leaf no.9 (16th node in the inclusion diagram above)
const proof = mmr.getProof(9)
console.log('Inclusion proof of leaf no.9', proof)
// Verifying the proof (throws on failure, pass on success)
mmr.verifyProof(proof)
console.log('Valid proof!')
// Inclusion proof of leaf no.9 {
// index: 9,
// value: '6',
// peaks: [ 15, 18, 19 ],
// peaksHashes: [
// '0x7811cf3bd6a5f019f9c345900f760694309d019be0766007388665145c431b3',
// '0x5ad94a9ad7f469929d8e513ddb87e8758bddc928b06dede8c9e248630ed48f9',
// '0x197f42d06f2cf19f82d475673f16350416f2c9180d77bea8a3bcc29d27b7325'
// ],
// siblingHashes: [
// '0x3531a94afdc03b1ee109786fdddaf23a7864c8f18ddff9d552b5dfb50ac66a',
// '0x41132c938a98be60612de7aed9daa905f91c8390f731c7fde8fb8bd59bbe4c3',
// '0x4a1fead9ecdd90793ba10b7da6e8a30d655843296f148f147a89cb3e978528'
// ],
// lastVisitedNodeIdx: 15
// }
// Valid proof!
```
[](https://github.com/HerodotusDev/merkle-mountain-ranges/blob/main/LICENSE)