public String signMap(Map<String, String> paramsToSign) {
        try {
            PrivateKey privateKey = getKey();
            Certificate certificate = getCert();
            StringBuilder toSign = new StringBuilder();
            for (String s : paramsToSign.values()) {
                toSign.append(s);
            }
            System.out.println("toSign:");
            System.out.println(toSign);
            byte[] data = toSign.toString().getBytes(StandardCharsets.UTF_8);
            String algorithmFromCert = certificate.getPublicKey().getAlgorithm();
            String algorithm = getAlgorithm(algorithmFromCert);
            Signature signature = Signature.getInstance(algorithm, JCP.PROVIDER_NAME);
            signature.initSign(privateKey);
            signature.update(data);

            byte[] secretBytes = signature.sign();
            return Base64.encodeBase64URLSafeString(secretBytes);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

sign = open(sign_file, "rb").read()
enc_sign = base64.b64encode(sign)
signed_data = pycades.SignedData()
signed_data.Content = "Random data"

try:
	signed_data.VerifyCades(enc_sign.decode("utf-8"), pycades.CADESCOM_CADES_BES, True)
except Exception:
	pass

cert = signed_data.Signers.Item(1).Certificate

Traceback (most recent call last):
  File "./sign.py", line 31, in <module>
    cert = signed_data.Signers.Item(1).Certificate
Exception: Internal error. (0x800B0100)