garrytan/gstack · error · Error

No decryption key available for ${prefix} cookies

Error message

No decryption key available for ${prefix} cookies

What it means

Error "No decryption key available for ${prefix} cookies" thrown in garrytan/gstack.

Source

Thrown at browse/src/cookie-import-browser.ts:692

function decryptCookieValue(row: RawCookie, keys: Map<string, Buffer>, platform: BrowserPlatform): string {
  // Prefer unencrypted value if present
  if (row.value && row.value.length > 0) return row.value;

  const ev = Buffer.from(row.encrypted_value);
  if (ev.length === 0) return '';

  const prefix = ev.slice(0, 3).toString('utf-8');

  // Chrome 127+ on Windows uses App-Bound Encryption (v20) — cannot be decrypted
  // outside the Chrome process. Caller should fall back to CDP extraction.
  if (prefix === 'v20') throw new CookieImportError(
    'Cookie uses App-Bound Encryption (v20). Use CDP extraction instead.',
    'v20_encryption',
  );

  const key = keys.get(prefix);
  if (!key) throw new Error(`No decryption key available for ${prefix} cookies`);

  if (platform === 'win32' && prefix === 'v10') {
    // Windows: AES-256-GCM — structure: v10(3) + nonce(12) + ciphertext + tag(16)
    const nonce = ev.slice(3, 15);
    const tag = ev.slice(ev.length - 16);
    const ciphertext = ev.slice(15, ev.length - 16);
    const decipher = crypto.createDecipheriv('aes-256-gcm', key, nonce) as crypto.DecipherGCM;
    decipher.setAuthTag(tag);
    return Buffer.concat([decipher.update(ciphertext), decipher.final()]).toString('utf-8');
  }

  // macOS / Linux: AES-128-CBC — structure: v10/v11(3) + ciphertext
  const ciphertext = ev.slice(3);
  const iv = Buffer.alloc(16, 0x20); // 16 space characters
  const decipher = crypto.createDecipheriv('aes-128-cbc', key, iv);
  const plaintext = Buffer.concat([decipher.update(ciphertext), decipher.final()]);

  // Chromium prefixes encrypted cookie payloads with 32 bytes of metadata.

View on GitHub (pinned to 94993f7401)

When it happens

Trigger: Thrown at browse/src/cookie-import-browser.ts:692 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of garrytan/gstack@94993f7401 (2026-08-12). Data as JSON: /api/errors/3517976b15cafb6b. Report an issue: GitHub.