Solidity - Hello World// SPDX-License-Identifier: MIT // Pragma solidity tells the compiler version. // In this case compiler version must be greater than or equal to 0.8.13 and less than 0.9.0 pragma solidity ^0.8.13; contract HelloWorld { string public welcome = "Hello Ethereum"; } The above contract is a basic hello world in solidity. Key conceptsSPDX - Blockchains are open space environment. Opening source code open can have legal implications. To maintina the trust we need to add the Lic...