private Map<String, Object> getSignedParams() { Map<String, Object> signedParams = (data != null) ? new HashMap<>(data) : new HashMap<String, Object>(); if (factoryId != null) signedParams.put("factory_id", factoryId); signedParams.put("access_key", credentials.getAccessKey()); signedParams.put("timestamp", timestamp != null ? timestamp : Utils.isoTimestamp()); Map<String, Object> additionalParams = new HashMap<>(signedParams); additionalParams.remove("file"); String signature = generateSignature(additionalParams); signedParams.put("signature", signature); return signedParams; }