Shielded Pool Contract

import { TransactionBlock } from '@mysten/sui.js/transactions';
import { poseidon } from '@identipay/crypto';

// Generate note commitment off-chain
const salt = randomBytes(32);
const commitment = poseidon([
  BigInt(amount),
  BigInt(ownerPubkey),
  BigInt(salt),
]);

// Deposit into pool
const tx = new TransactionBlock();
tx.moveCall({
  target: `${PACKAGE_ID}::shielded_pool::deposit`,
  typeArguments: [USDC_TYPE],
  arguments: [
    tx.object(POOL_ID),
    tx.object(coinId),
    tx.pure(commitment.toString()),
  ],
});

await wallet.signAndExecuteTransactionBlock({ transactionBlock: tx });

// Store note for later withdrawal
const note = { amount, ownerPubkey, salt, leafIndex, commitment };
saveNote(note);

import { generatePoolWithdrawProof } from '@identipay/zk';

// Find a note to spend
const note = await findNote(amount);

// Generate Merkle proof for this note
const { merkleProof, merkleRoot } = await getMerkleProof(
  note.leafIndex
);

// Generate nullifier
const nullifier = poseidon([note.commitment, ownerPrivateKey]);

// Generate ZK proof
const { proof, publicInputs } = await generatePoolWithdrawProof({
  note,
  merkleProof,
  merkleRoot,
  nullifier,
  recipient: freshStealthAddress,
  withdrawAmount: amount,
  changeCommitment: 0, // full withdrawal
});

// Execute withdrawal
const tx = new TransactionBlock();
tx.moveCall({
  target: `${PACKAGE_ID}::shielded_pool::withdraw`,
  typeArguments: [USDC_TYPE],
  arguments: [
    tx.object(POOL_ID),
    tx.object(VK_ID),
    tx.pure(proof),
    tx.pure(publicInputs),
    tx.pure(nullifier.toString()),
    tx.pure(freshStealthAddress),
    tx.pure(amount),
    tx.pure('0'), // no change
  ],
});

await wallet.signAndExecuteTransactionBlock({ transactionBlock: tx });