whsiper messaging.js

// Create a key pair
web3.shh.newKeyPair();
.then(console.log);
> "5e57b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f"

// Check key pair exist
web3.shh.hasKeyPair('fe22b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f');
.then(console.log);
> true

//generate a symmetric key
web3.shh.newSymKey();
.then(console.log);
> "cec94d139ff51d7df1d228812b90c23ec1f909afa0840ed80f1e04030bb681e4"

// send symmetric key to the receiver
web3.shh.addSymKey('0x5e11b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f');
.then(console.log);
> "fea94d139ff51d7df1d228812b90c23ec1f909afa0840ed80f1e04030bb681e4"

// Post the whisper message
var identities = [];
var subscription = null;

Promise.all([
    web3.shh.newSymKey().then((id) => {identities.push(id);}),
    web3.shh.newKeyPair().then((id) => {identities.push(id);})

}).then(() => {

    // will receive also its own message send, below
    subscription = shh.subscribe("messages", {
        symKeyID: identities[0],
        topics: ['0xffaadd11']
    }).on('data', console.log);

}).then(() => {
   shh.post({
        symKeyID: identities[0], // encrypts using the sym key ID
        sig: identities[1], // signs the message using the keyPair ID
        ttl: 10,
        topic: '0xffaadd11',
        payload: '0xffffffdddddd1122',
        powTime: 3,
        powTarget: 0.5
    })
});


// subscribe for incoming message
web3.shh.subscribe('messages', {
    symKeyID: 'bf31b9ffc2387e18636e0a3d0c56b023264c16e78a2adcba1303cefc685e610f',
    sig: '0x04d1574d4eab8f3dde4d2dc7ed2c4d699d77cbbdd09167b8fffa099652ce4df00c4c6e0263eafe05007a46fdf0c8d32b11aeabcd3abbc7b2bc2bb967368a68e9c6'
    ttl: 20,
    topic: '0xffddaa11',
    minPow: 0.8,
}, function(error, message, subscription){

    console.log(message);
    > {
        "hash": "0x4158eb81ad8e30cfcee67f20b1372983d388f1243a96e39f94fd2797b1e9c78e",
        "padding": "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",
        "payload": "0xdeadbeaf",
        "pow": 0.5371803278688525,
        "recipientPublicKey": null,
        "sig": null,
        "timestamp": 1496991876,
        "topic": "0x01020304",
        "ttl": 50
    }
})
// or
.on('data', function(message){ ... });