symkey.js

const Web3 = require('web3');
const web3 = new Web3('ws://localhost:8546');
const shh = web3.shh;


// Generate Symkey From password   
// https://github.com/ethereum/go-ethereum/wiki/Whisper-Usage#generatesymkeyfrompassword
shh.generateSymKeyFromPassword("hello").then((symKeyID) => {

    console.log('This is symkey ID unique foe every run:  ', symKeyID);

    // Get symkey from local node by useing symKeyID
    // https://github.com/ethereum/go-ethereum/wiki/Whisper-Usage#generatesymkeyfrompassword 
    shh.getSymKey(symKeyID).then((symKey) => {
        console.log('This is identical symkey : ',  symKey);
    })

})