static bool isSignedWithKey_verbose;

// TODO: replace fullTrim with something else!!
static boolean isSignedWithKey(S signed, S key) {
  try {
    L<S> lines = toLines(signed);
    S sigLine = lines.get(lines.size()-1);
    S text = fromLines(lines.subList(0, lines.size()-1));
    S sig = dropPrefixMandatory("sig: ", sigLine);
    ret PKI.verifySignature(PKI.publicKeyFromString(key), PKI.signatureFromString(sig), toUtf8(text));
  } catch (RuntimeException e) {
    if (isSignedWithKey_verbose)
      printStackTrace(e);
    ret false;
  }
}