godprotocol/server/utils.js

A distributed computing environment for Web 4.0 — integrating AI, decentralisation, and virtual computation.

import crypto, { createHash, randomBytes, createCipheriv } from "crypto";

const deriveKey = (secret) =>
  createHash("sha256").update(String(secret)).digest();
/**
 * Encrypt a value (usually a session token) using AES-256-GCM.
 * Returns a compact base64 string encoding iv|authTag|ciphertext.
 */
const decryptToken = (enc, secret) => {
  if (!enc) return null;

  try {
    const key = deriveKey(secret);

    const parts = enc.split(":");
    if (parts.length < 3) throw new Error("Invalid token format");

    const iv = Buffer.from(parts[0], "base64");
    const tag = Buffer.from(parts[1], "base64");
    const data = Buffer.from(parts.slice(2).join(":"), "base64");

    const decipher = createDecipheriv("aes-256-gcm", key, iv);
    decipher.setAuthTag(tag);

    const decrypted = Buffer.concat([
      decipher.update(data),
      decipher.final(),
    ]).toString("utf8");

    return JSON.parse(decrypted);
  } catch (err) {
    console.error("❌ Decrypt failed:", err.message);
    return null;
  }
};

const encryptToken = (payload, secret) => {
  const key = deriveKey(secret);
  const iv = randomBytes(12); // GCM standard

  const cipher = createCipheriv("aes-256-gcm", key, iv);

  const encrypted = Buffer.concat([
    cipher.update(JSON.stringify(payload), "utf8"),
    cipher.final(),
  ]);

  const tag = cipher.getAuthTag();

  // iv:tag:data
  return `${iv.toString("base64")}:${tag.toString("base64")}:${encrypted.toString("base64")}`;
};

export { encryptToken, decryptToken };