Create Nullifier PDAs - Light Protocol

For some use cases, such as sending payments, you might want to prevent your onchain instruction from being executed more than once. The nullifier program utility solves this for you. We also deployed a reference implementation to public networks so you can get started quickly:


Program ID	`NFLx5WGPrTHHvdRNsidcrNcLxRruMC92E4yv7zhZBoT`
Networks	Mainnet, Devnet
Source code	github.com/Lightprotocol/nullifier-program
Example Tx	Solana Explorer

For the usage example source code, see here: create_nullifier.rs

How It Works

Derives PDA from ["nullifier", id] seeds (where id is your unique identifier, e.g. a nonce, uuid, hash of signature, etc.)
Creates an empty rent-free PDA at that address
If the address exists, the whole transaction fails
Prepend or append this instruction to your transaction.

Dependencies

Rust
TS

[dependencies]
light-nullifier-program = "0.1.2"
light-client = "0.19.0"

npm install @lightprotocol/nullifier-program @lightprotocol/stateless.js@beta

Using the Helper

Rust
TS

use light_nullifier_program::sdk::{create_nullifier_ix, PROGRAM_ID};
use light_client::{LightClient, LightClientConfig};
use solana_sdk::{system_instruction, transaction::Transaction};

let mut rpc = LightClient::new(
    LightClientConfig::new("https://mainnet.helius-rpc.com/?api-key=...")
).await?;

// Create a unique 32-byte ID
let id: [u8; 32] = /* hash of payment inputs or random */;

// Build nullifier instruction
let nullifier_ix = create_nullifier_ix(&mut rpc, payer.pubkey(), id).await?;

// Combine with your transaction
let transfer_ix = system_instruction::transfer(&payer.pubkey(), &recipient, 1_000_000);
let tx = Transaction::new_signed_with_payer(
    &[nullifier_ix, transfer_ix],
    Some(&payer.pubkey()),
    &[&payer],
    recent_blockhash,
);

import { createNullifierIx } from "@lightprotocol/nullifier-program";
import { createRpc } from "@lightprotocol/stateless.js";
import { Transaction, SystemProgram, ComputeBudgetProgram } from "@solana/web3.js";

const rpc = createRpc("https://mainnet.helius-rpc.com/?api-key=...");

// Create a unique 32-byte ID (e.g., hash of payment inputs)
const id = new Uint8Array(32);
crypto.getRandomValues(id);

// Build nullifier instruction
const nullifierIx = await createNullifierIx(rpc, payer.publicKey, id);

// Combine with your transaction
const tx = new Transaction().add(
  nullifierIx,
  // your main instruction
  SystemProgram.transfer({
    fromPubkey: payer.publicKey,
    toPubkey: recipient,
    lamports: 1_000_000,
  })
);

Manually Fetching Proof

Rust
TS

use light_nullifier_program::sdk::{fetch_proof, build_instruction};

// Step 1: Fetch proof
let proof_result = fetch_proof(&mut rpc, &id).await?;

// Step 2: Build instruction
let nullifier_ix = build_instruction(payer.pubkey(), id, proof_result);

// Add to transaction
let tx = Transaction::new_signed_with_payer(
    &[nullifier_ix, transfer_ix],
    Some(&payer.pubkey()),
    &[&payer],
    recent_blockhash,
);

import { fetchProof, buildInstruction } from "@lightprotocol/nullifier-program";

// Step 1: Fetch proof
const proofResult = await fetchProof(rpc, id);

// Step 2: Build instruction
const nullifierIx = buildInstruction(payer.publicKey, id, proofResult);

// Combine with your transaction
const tx = new Transaction().add(
  nullifierIx,
  // your main instruction
  SystemProgram.transfer({
    fromPubkey: payer.publicKey,
    toPubkey: recipient,
    lamports: 1_000_000,
  })
);

Check If Nullifier Exists

Rust
TS

use light_nullifier_program::sdk::derive_nullifier_address;

let address = derive_nullifier_address(&id);
let account = rpc.get_compressed_account(None, Some(address)).await?;
let exists = account.value.is_some();

import { deriveNullifierAddress } from "@lightprotocol/nullifier-program";
import { bn } from "@lightprotocol/stateless.js";

const address = deriveNullifierAddress(id);
const account = await rpc.getCompressedAccount(bn(address.toBytes()));
const exists = account !== null;

Note that this is a reference implementation. Feel free to fork the program as you see fit.

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