panels-origin/api/docs_crypto.ts

import { fromHex, toHex } from "./crypto.ts";
import { config } from "./config.ts";

async function docsKey(): Promise<CryptoKey> {
  const raw = fromHex(config.docsKeyHex);
  if (raw.length !== 32) {
    throw new Error("DOCS_KEY must be 64 hex chars (32 bytes)");
  }
  return await crypto.subtle.importKey("raw", raw, "AES-GCM", false, ["encrypt", "decrypt"]);
}

export async function encryptBytes(plain: Uint8Array): Promise<{ iv: string; cipher: Uint8Array }> {
  const key = await docsKey();
  const iv = crypto.getRandomValues(new Uint8Array(12));
  const cipher = new Uint8Array(
    await crypto.subtle.encrypt({ name: "AES-GCM", iv }, key, plain),
  );
  return { iv: toHex(iv), cipher };
}

export async function decryptBytes(ivHex: string, cipher: Uint8Array): Promise<Uint8Array> {
  const key = await docsKey();
  const iv = fromHex(ivHex);
  return new Uint8Array(
    await crypto.subtle.decrypt({ name: "AES-GCM", iv }, key, cipher),
  );
}