Extract functionality for reading device id from crypto chip from begin method to dedicated util class CryptoUtil for better readability

Author: aentinger

src/ArduinoIoTCloudTCP.cpp

@@ -23,6 +23,7 @@
   #include "utility/crypto/ECCX08Cert.h"
   #include "utility/crypto/BearSSLTrustAnchor.h"
   #include <ArduinoECCX08.h>
+  #include "utility/crypto/CryptoUtil.h"
 #endif
 
 TimeService time_service;
@@ -31,7 +32,6 @@ TimeService time_service;
   const static int keySlot									                 = 0;
   const static int compressedCertSlot						             = 10;
   const static int serialNumberAndAuthorityKeyIdentifierSlot = 11;
-  const static int deviceIdSlot								               = 12;
 #endif
 
 const static int CONNECT_SUCCESS							               = 1;
@@ -81,17 +81,13 @@ int ArduinoIoTCloudTCP::begin(String brokerAddress, uint16_t brokerPort) {
   _brokerPort = brokerPort;
 
   #ifdef BOARD_HAS_ECCX08
-  byte deviceIdBytes[72];
   if (!ECCX08.begin()) {
     Debug.print(DBG_ERROR, "Cryptography processor failure. Make sure you have a compatible board.");
     return 0;
   }
 
-  if (!ECCX08.readSlot(deviceIdSlot, deviceIdBytes, sizeof(deviceIdBytes))) {
-    Debug.print(DBG_ERROR, "Cryptography processor read failure.");
-    return 0;
-  }
-  _device_id = (char*)deviceIdBytes;
+  _device_id = CryptoUtil::readDeviceId(ECCX08, ECCX08Slot::DeviceId);
+  if(_device_id.length() == 0) { Debug.print(DBG_ERROR, "Cryptography processor read failure."); return 0; }
 
   if (!ECCX08Cert.beginReconstruction(keySlot, compressedCertSlot, serialNumberAndAuthorityKeyIdentifierSlot)) {
     Debug.print(DBG_ERROR, "Cryptography certificate reconstruction failure.");

src/utility/crypto/CryptoUtil.cpp

@@ -0,0 +1,41 @@
+/*
+   This file is part of ArduinoIoTCloud.
+
+   Copyright 2019 ARDUINO SA (http://www.arduino.cc/)
+
+   This software is released under the GNU General Public License version 3,
+   which covers the main part of arduino-cli.
+   The terms of this license can be found at:
+   https://www.gnu.org/licenses/gpl-3.0.en.html
+
+   You can be released from the requirements of the above licenses by purchasing
+   a commercial license. Buying such a license is mandatory if you want to modify or
+   otherwise use the software for commercial activities involving the Arduino
+   software without disclosing the source code of your own applications. To purchase
+   a commercial license, send an email to [email protected].
+*/
+
+/******************************************************************************
+   INCLUDE
+ ******************************************************************************/
+
+#include "CryptoUtil.h"
+
+#ifdef BOARD_HAS_ECCX08
+
+/******************************************************************************
+   PUBLIC MEMBER FUNCTIONS
+ ******************************************************************************/
+
+String CryptoUtil::readDeviceId(ECCX08Class & eccx08, ECCX08Slot const slot)
+{
+  byte device_id_bytes[72] = {0};
+  
+  if (eccx08.readSlot(static_cast<int>(slot), device_id_bytes, sizeof(device_id_bytes))) {
+   return String(reinterpret_cast<char *>(device_id_bytes));
+  } else {
+   return String("");
+  }  
+}
+
+#endif /* BOARD_HAS_ECCX08 */

src/utility/crypto/CryptoUtil.h

@@ -0,0 +1,64 @@
+/*
+   This file is part of ArduinoIoTCloud.
+
+   Copyright 2019 ARDUINO SA (http://www.arduino.cc/)
+
+   This software is released under the GNU General Public License version 3,
+   which covers the main part of arduino-cli.
+   The terms of this license can be found at:
+   https://www.gnu.org/licenses/gpl-3.0.en.html
+
+   You can be released from the requirements of the above licenses by purchasing
+   a commercial license. Buying such a license is mandatory if you want to modify or
+   otherwise use the software for commercial activities involving the Arduino
+   software without disclosing the source code of your own applications. To purchase
+   a commercial license, send an email to [email protected].
+*/
+
+#ifndef ARDUINO_IOT_CLOUD_UTILITY_CRYPTO_CRYPTO_UTIL_H_
+#define ARDUINO_IOT_CLOUD_UTILITY_CRYPTO_CRYPTO_UTIL_H_
+
+/******************************************************************************
+   INCLUDE
+ ******************************************************************************/
+
+#include <ArduinoIoTCloud_Defines.h>
+
+#ifdef BOARD_HAS_ECCX08
+
+#include <Arduino.h>
+#include <ArduinoECCX08.h>
+
+/******************************************************************************
+   TYPEDEF
+ ******************************************************************************/
+
+enum class ECCX08Slot : int
+{
+  Key                                   = 0,
+  CompressedCertificate                 = 10,
+  SerialNumberAndAuthorityKeyIdentifier = 11,
+  DeviceId                              = 12
+};
+
+/******************************************************************************
+   CLASS DECLARATION
+ ******************************************************************************/
+
+class CryptoUtil
+{
+public:
+
+  static String readDeviceId(ECCX08Class & eccx08, ECCX08Slot const slot);
+
+
+private:
+
+  CryptoUtil() { }
+  CryptoUtil(CryptoUtil const & other) { }
+
+};
+
+#endif /* BOARD_HAS_ECCX08 */
+
+#endif /* ARDUINO_IOT_CLOUD_UTILITY_CRYPTO_CRYPTO_UTIL_H_ */