Censorship-resistant short messaging built on the Ethereum blockchain, built and demoed at ETHWaterloo 2017.
The app relies upon this simple Solidity contract:
pragma solidity ^0.4.15;
contract Transponder {
address public owner;
event Squawk(address indexed _author, string _text);
function Transponder() {
owner = msg.sender;
}
function squawk(string _text) {
Squawk(msg.sender, _text);
}
}