@Override
    protected void engineInit(Key key, AlgorithmParameterSpec params,
            SecureRandom random) throws InvalidKeyException, InvalidAlgorithmParameterException {
        // ECDH doesn't need an AlgorithmParameterSpec
        if (params != null) {
          throw new InvalidAlgorithmParameterException("No algorithm parameters supported");
        }
        engineInit(key, random);
    }
Returns the expected result length for the given {@code key}.
common/src/main/java/org/conscrypt/OpenSSLBaseDHKeyAgreement.java