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README.md

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-# SecureIoT_ArduinoServer
+Secure IOT (Arduino Server)
+---------------------------
 
-Secure IoT command sending (Arduino Server).
 There are many ways to secure and authenticate a networking communication, but not all solutions will run on a microcontroller, where processing power and memory is a scarce resource.
+
+How does it work?
+~~~~~~~~~~~~~~~~~
+
++Server -> the iot device that will receive the command+
+
++Client -> the command sender+
+
+
+. The Client connects to the Server.
+
+. [ Optional: The Client sends a predefined ammount of data for the Server to wake up. (Some libraries need the client to send first data, else they will not recognize that a connection was just made.) ]
+
+. The Server sends a challenge to be solved.
+
+. The Client send the solved challenge with the command.
+
+. The Server extracts the command from the response/solution, executes it [Optional: sends back the response ].
+
+. [ Optional: The Client extracs the execution response from the Server response. ]
+
+
+
+Implementation
+~~~~~~~~~~~~~~
+
+Server + Client Requirements
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- set the same initial data length (0-n)
+- set the same hashing function
+- set the same symmetric password
+
+Data
+^^^^
+
+. [ Optional: Client Sends: 1-n bytes (wake up packet) ]
+
+. Server: Sends Challenge (1-n bytes)
+
+. Client: Sends solved challenge ( Len(hash) bytes)
+
+. [ Optional: Server: Sends Response ( Len(hash) bytes) ]
+
+
+Methodology
+^^^^^^^^^^^
+
+. [ Optional: The Client after connection, sends a predefined number of bytes. ]
+
+. The Server generates and sends a random number (bigger -> more secure) for each connection.
+. The Client calculates and sends the HMAC of (random server data + command) using the shared secret password
+
+. The Server tries to find what possible command could the Client have sent 
+(calculates HMAC of random server data + possible command, using the shared secret password and compares them)
+and then calls the corresponding function. [ Optional: The response of that function is then calculated 
+(HMAC of random server data + response, using the shared secret password) and sent to the Client. ]
+
+. [ Optional: The Client tries to find what possible response command could the Server have sent
+(calculates HMAC of random server data + response command, using the shared secret password) ]
+
+
+
+Considerations
+~~~~~~~~~~~~~~
+
+Pros
+^^^^
+
+- Minimalistyc nor verbose
+- minimal memory usage*
+- minimal cpu usage*
+- fast**
+- authentication
+- confidentiality
+- replay protection
+
+*with the use of appropriate hashing functions
+
+**when a limited ammount of commands is used
+
+Cons
+^^^^
+
+- uses symetric cryptography
+- is not designed to send multiple bytes (1 byte commands recommended)
+- requires a random seed
+
+Proof of Concept
+~~~~~~~~~~~~~~~~
+
+Tested and fully working demo is attached!
+
+This demo was implemented on a pc (Node.JS Client) and an arduino pro mini with an ethernet shield (Server).