On-Chain Confidential Storage

import { ethers } from "ethers";

const BASE_URL = "https://cifer-blackbox.ternoa.dev:3010";
const CHAIN_ID = 752025;
const VAULT_ADDRESS = "0x6A8b01CA9AB653510F579cfB59502880DCD0F174";

async function encryptAndStore(plainText, keyLabel) {
  // 1. Setup
  const provider = new ethers.BrowserProvider(window.ethereum);
  const signer = await provider.getSigner();
  const walletAddress = await signer.getAddress();
  
  // 2. Get current block number
  const health = await fetch(`${BASE_URL}/healthz`).then(r => r.json());
  const blockNumber = health.chainStatus[CHAIN_ID].lastKnownBlockNumber;
  
  // 3. Get user's secretId from vault
  const vault = new ethers.Contract(VAULT_ADDRESS, [
    "function userSecretId(address) view returns (uint256)",
    "function store(bytes32, bytes, bytes)"
  ], signer);
  
  const secretId = await vault.userSecretId(walletAddress);
  
  // 4. Build and sign encrypt payload
  const dataString = `${CHAIN_ID}_${secretId}_${walletAddress}_${blockNumber}_${plainText}`;
  const signature = await signer.signMessage(dataString);
  
  // 5. Call encrypt API
  const encryptResponse = await fetch(`${BASE_URL}/encrypt-payload`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      data: dataString,
      signature: signature,
      outputFormat: "hex"
    })
  });
  
  const { cifer, encryptedMessage } = await encryptResponse.json();
  
  // 6. Store on-chain
  const keyBytes = ethers.toUtf8Bytes(keyLabel);
  const key = ethers.zeroPadValue(ethers.hexlify(keyBytes), 32);
  
  const tx = await vault.store(key, encryptedMessage, cifer);
  const receipt = await tx.wait();
  
  return { key, blockNumber: receipt.blockNumber, txHash: receipt.hash };
}

// Usage
const result = await encryptAndStore("My secret data", "note-001");
console.log("Stored at block:", result.blockNumber);

async function retrieveAndDecrypt(keyLabel) {
  const provider = new ethers.BrowserProvider(window.ethereum);
  const signer = await provider.getSigner();
  const walletAddress = await signer.getAddress();
  
  // Convert key label to bytes32
  const keyBytes = ethers.toUtf8Bytes(keyLabel);
  const key = ethers.zeroPadValue(ethers.hexlify(keyBytes), 32);
  
  // Get metadata from vault
  const vault = new ethers.Contract(VAULT_ADDRESS, [
    "function userSecretId(address) view returns (uint256)",
    "function getUserMetadata(address, bytes32) view returns (uint256, uint256)",
    "function computeDataId(address, bytes32) view returns (bytes32)"
  ], provider);
  
  const secretId = await vault.userSecretId(walletAddress);
  const metadata = await vault.getUserMetadata(walletAddress, key);
  const dataId = await vault.computeDataId(walletAddress, key);
  
  // Fetch event logs to get cifer + encryptedMessage
  const storedAtBlock = Number(metadata[1]);
  const logs = await provider.getLogs({
    address: VAULT_ADDRESS,
    fromBlock: storedAtBlock - 50,
    toBlock: storedAtBlock + 50
  });
  
  // Parse CIFERDataStored event
  const vaultInterface = new ethers.Interface([
    "event CIFERDataStored(bytes32 indexed dataId, address indexed user, bytes32 indexed key, bytes cifer, bytes encryptedMessage)"
  ]);
  
  let cifer, encryptedMessage;
  for (const log of logs) {
    try {
      const parsed = vaultInterface.parseLog(log);
      if (parsed.args.dataId === dataId) {
        cifer = parsed.args.cifer;
        encryptedMessage = parsed.args.encryptedMessage;
        break;
      }
    } catch { /* not our event */ }
  }
  
  // Get fresh block number and decrypt
  const health = await fetch(`${BASE_URL}/healthz`).then(r => r.json());
  const blockNumber = health.chainStatus[CHAIN_ID].lastKnownBlockNumber;
  
  const dataString = `${CHAIN_ID}_${secretId}_${walletAddress}_${blockNumber}_${encryptedMessage}`;
  const signature = await signer.signMessage(dataString);
  
  const decryptResponse = await fetch(`${BASE_URL}/decrypt-payload`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      cifer: cifer,
      data: dataString,
      signature: signature,
      inputFormat: "hex"
    })
  });
  
  const { decryptedMessage } = await decryptResponse.json();
  return decryptedMessage;
}

// Usage
const plainText = await retrieveAndDecrypt("note-001");
console.log("Decrypted:", plainText);