getSignedCookie function
Implementation
Future<String?> getSignedCookie(
Context c,
String secret,
String key,
) async {
final cookies = getCookies(c);
final raw = cookies[key];
if (raw == null) return null;
final parts = raw.split('.');
if (parts.length != 2) return null;
final value = parts[0];
final sig = parts[1];
final expected = _sign(value, secret);
if (sig != expected) return null;
return value;
}