What is TLS/SSL
First questions comes in mind, what TLS and SSL is. TLS mainly stand for Transport Layer Secuirty. And this is the successor to SSL(Secure Sockets Layer). TLS along with SSL is used for cryptographic protocols to secure communication over the web.
Well TLS uses pubic key cryptography to encrypt messages. It encrypts communication generally on the TCP layer.
What is public key cryptography
In public key cryptography, each client and each server has tow keys mainly:-
(1)Public Key
(2)Private Key
Public key is shared with everyone and private key is secured. And to encrypt a message, a computer requires its private key and the recipient?s public key. While on the other hand, to decrypt the message, the recipient requires its own.
And to get access the module you need to use
require('tls')
syntax:
var tls=require('tls');
The tls module uses OpenSSL to attain Transport Layer Security and Secure Socket Layer. Well TLS/SSL is a public/private key infrastruture. Each client and each server must have a private key.
And a private key can be created like this:-
openssl genrsa -out ryans-key.pem 1024
All servers and some clients need to have a certificate. Certificates are public keys signed by a Certificate Authority or self-signed. And to get certificate, you have to create a "Certificate Signing Request" CSR file.
And a certificate can be created like below
openssl req -new -key ryans-key.pem -out ryans-csr.pem
And to create a self-signed certificate with the CSR:-
openssl x509 -req -in ryans-csr.pem -signkey ryans-key.pem -out ryans-cert.pem
Node.js TLS client example
File:tlsclient.js
tls = require('tls');
function connected(stream) {
if (stream) {
// socket connected
stream.write("GET / HTTP/1.0\n\rHost: encrypted.google.com:443\n\r\n\r");
} else {
console.log("Connection failed");
}
}
// needed to keep socket variable in scope
var dummy = this;
// try to connect to the server
dummy.socket = tls.connect(443, 'encrypted.google.com', function() {
// callback called only after successful socket connection
dummy.connected = true;
if (dummy.socket.authorized) {
// authorization successful
dummy.socket.setEncoding('utf-8');
connected(dummy.socket);
} else {
// authorization failed
console.log(dummy.socket.authorizationError);
connected(null);
}
});
dummy.socket.addListener('data', function(data) {
// received data
console.log(data);
});
dummy.socket.addListener('error', function(error) {
if (!dummy.connected) {
// socket was not connected, notify callback
connected(null);
}
console.log("FAIL");
console.log(error);
});
dummy.socket.addListener('close', function() {
// do something
});
Now we open th Node.js command prompt and execuet the file
node tlsclient.js
