RSA Encryption between device and post-bridge

server/.gitignore

@@ -0,0 +1,3 @@
+crypto/keys
+node_modules
+npm-debug.log

server/app.js

@@ -10,6 +10,11 @@ var routDevices = require('./routes/devices');
 const config = require("./config/database")//requiring database folder
 var subscrib = require('./subscribe_post');
 
+/**
+ * Create public and private keys of client and store them in file
+ */
+const rsaWrapper = require('./crypto/rsa-wrapper');
+rsaWrapper.generateIfRequired('server');
 
 var app = express();
 

server/crypto/init.js

@@ -0,0 +1,5 @@
+const rsaWrapper = require('./rsa-wrapper');
+// generate opened and closed keys for browser and server
+rsaWrapper.generate('server');
+rsaWrapper.generate('client');
+console.log('Keys generated …');

server/crypto/rsa-wrapper.js

@@ -0,0 +1,63 @@
+const path = require('path');
+const rsaWrapper = {};
+const fs = require('fs');
+const NodeRSA = require('node-rsa');
+const crypto = require('crypto');
+
+// load keys from file
+rsaWrapper.initLoadServerKeys = (basePath) => {
+    rsaWrapper.serverPub = rsaWrapper.loadKey(basePath, 'server', 'public');
+    rsaWrapper.serverPrivate = rsaWrapper.loadKey(basePath, 'server', 'private');
+    rsaWrapper.clientPub = rsaWrapper.loadKey(basePath, 'client', 'private');
+};
+
+rsaWrapper.loadKey = (basePath, direction, type) => {
+    return fs.readFileSync(path.resolve(basePath, 'keys', `${direction}.${type}.pem`));
+};
+
+rsaWrapper.generate = (direction) => {
+    let key = new NodeRSA();
+    key.generateKeyPair(2048, 65537);
+    fs.writeFileSync(path.resolve(__dirname, 'keys', direction + '.private.pem'), key.exportKey('pkcs8-private-pem'));
+    fs.writeFileSync(path.resolve(__dirname, 'keys', direction + '.public.pem'), key.exportKey('pkcs8-public-pem'));
+
+    return true;
+};
+
+rsaWrapper.generateIfRequired = (direction) => {
+    const exists = fs.existsSync(path.resolve(__dirname, 'keys', direction + '.private.pem'))
+        && fs.existsSync(path.resolve(__dirname, 'keys', direction + '.public.pem'));
+
+    return exists || this.generate(direction);
+}
+
+rsaWrapper.serverExampleEncrypt = () => {
+    console.log('Server public encrypting');
+
+    let enc = rsaWrapper.encrypt(rsaWrapper.serverPub, '{"sensor":"PIR","temperature":"44.77","humidity":"86.46","userid":"nakwarsi"}');
+    console.log('Encrypted RSA string ', '\n', enc);
+    let dec = rsaWrapper.decrypt(rsaWrapper.serverPrivate, enc);
+    console.log('Decrypted RSA string ...');
+    console.log(dec);
+};
+
+rsaWrapper.encrypt = (publicKey, message) => {
+    let enc = crypto.publicEncrypt({
+        key: publicKey,
+        padding: crypto.constants.RSA_PKCS1_OAEP_PADDING
+    }, Buffer.from(message));
+
+    return enc.toString('base64');
+};
+
+rsaWrapper.decrypt = (privateKey, message) => {
+    console.log('crypto.RSA_PKCS1_OAEP_PADDING', crypto.RSA_PKCS1_OAEP_PADDING);
+    let enc = crypto.privateDecrypt({
+        key: privateKey,
+        padding: crypto.constants.RSA_PKCS1_OAEP_PADDING
+    }, Buffer.from(message, 'base64'));
+
+    return enc.toString();
+};
+
+module.exports = rsaWrapper;

server/package.json

@@ -15,6 +15,7 @@
     "mongoose": "^5.1.6",
     "morgan": "~1.9.0",
     "mqtt": "^2.18.1",
+    "node-rsa": "^1.0.0",
     "request": "^2.87.0"
   }
 }

server/subscribe_post.js

@@ -8,13 +8,20 @@ var client = mqtt.connect('mqtt://localhost:1883');
 //var db_sensor = require('../mongoose/database');
 let message;
 
+const rsaWrapper = require('./crypto/rsa-wrapper');
+let serverPrivateKey;
+
 var connectCallback = function () {
     console.log('mqtt broker connected')
-    client.subscribe('question2')
+    client.subscribe('question2');
+    serverPrivateKey = rsaWrapper.loadKey('./crypto', 'server', 'private');
 }
 
-client.on('message', function (topic, msg) {   
-    message = JSON.parse(msg);   
+client.on('message', function (topic, msg) {
+    const decrypted = rsaWrapper.decrypt(serverPrivateKey, msg.toString('utf8'));
+    console.log('DECRYPTED Message - ', decrypted);
+
+    message = JSON.parse(decrypted);   
     let DATA = {
         sensor: message.sensor,
         temperature: message.temperature,

server/virtualDevice.js

@@ -6,6 +6,15 @@ var interval_time = 1
 var it = 5;
 var interval = -1;
 
+/**
+ * Create public and private keys of client and store them in file
+ */
+const rsaWrapper = require('./crypto/rsa-wrapper');
+rsaWrapper.generateIfRequired('client');
+
+const serverPublicKey = rsaWrapper.loadKey('./crypto', 'server', 'public');
+console.log('Sercver Public *******************', serverPublicKey);
+
 
 function sentData()
 {
@@ -15,8 +24,11 @@ function sentData()
             humidity: (Math.random() * 100).toFixed(2),
             userid: sen[Math.floor((Math.random() * 3).toFixed(2))]
         }
-        console.log('sent');      
-        client.publish('question2', JSON.stringify(data))
+
+        const encrypted = rsaWrapper.encrypt(serverPublicKey,JSON.stringify(data));
+        console.log('\nDATA - ', encrypted);
+
+        client.publish('question2', encrypted);
         it = interval_time
 }