This is a project in which the Blockchain and IoT are used to safely track Cetara anchovies. The work was carried out in collaboration with BilancioCO2 Zero, a Unicam spinoff, and Silthenia S.r.l, a startup from Montedinove (AP).
It is complementary to that of Riccardo Petracci, a fellow magistral that has developed an IoT device that records the various GPS informations and uploads it to a Database. What was missing was the development of an Arduino library to send tracking data (latitude, longitude, altitude, unixtime, device id and box fish id) to the Blockchain and of a Smart Contract that receive these to uploads them to this protocol.
In this branch you can find the last version of the project where the Smart Contract, instead to receive several bytes32, will receive only a bytes data type. This data will be an hexadecimal string of a JSON string that contains all the tracks made by a device in one day. The difference with the first version (which is in the first_version branch) is that only one transaction needs to be sent becaues the JSON string is updated every time that the device tracks a new box fish and at the end of the job the string will be sent to the Blockchain.
The work focused on the creation, with Arduino, of a raw transaction to be sent via Json-RPC. A module was written for the RLP encoding and an other for the signing mechanism with ECDSA.
The external library used for signature are:
- keccak.k for Keccak256 hash;
- secp256k1_recovery.h for signature with secp256k1 curve of ECDSA.
For privacy reason the sensitive data have been removed, so in order to use the Arduino library the code must be modified adding the missing information.
For privacy reason the sensitive data have been removed, so in order to use the Arduino library the code must be modified adding the missing information.
- In Credentials.cpp you must add:
the ssid and password in connectWPA2();
const char* ssid = "";
const char* password = "";
or the ssid, password and username in connectWPA2Enterprise().
const char* ssid = "";
const char* username = "";
const char* password = "";
- In RawTransaction.cpp it is necessary to add:
the WALLET_ADDRESS in String createRawTransaction(String data, String privateKey). The wallet address must match the privateKey;
String nonce = getNonce(WALLET_ADDRESS);
the CONTRACT_ADDRESS and CHAIN_ID must also be added in this method;
Tx tx = {nonce, "0x", gasLimit, CONTRACT_ADDRESS, "0x", data, String(CHAIN_ID, HEX), "0x", "0x"};
- In RpcRequest.cpp:
it's good to enter the Ethereum node (HOST) and the PORT to which send Json-RPC request.
const char server[] = HOST;
const int port = PORT;
- At the end you must modified the file ethereumTx_arduino.ino:
first you have to connect the board to WiFi with connectWPA2Mobile() or connectWPA2Home() and then create the dataField with JSON needed.
String dataField = createDataField(/* json data */);
This variable, with the PRIVATE_KEY is used to create the raw transaction
String rawTx = createRawTransaction(dataField, PRIVATE_KEY);
to be sent with sendRawTransaction(rawTx) that return the transaction hash if there isn't problems.
For testing with web3.js it is necessary to edit the .env file:
BESU_NODE=#ethereum node
PRIVATE_KEY=#own private key
CONTRACT_ADDRESS=#contract address
ADMIN_SECRET_KEY=#adim private key
The ADMIN_SECRET_KEY must match the public address in the method addDevice(bytes32 _idDevice, address _deviceAddress) of the Solidity Smart Contract:
require(msg.sender == /* wallet address of admin */, "Only admin can add addresses");