Yes this is because there is some security protocol initiation called Transport Layer protocol for everything which involves security in internet. I would like to give you a brief idea about TLS which is the successor of SSL ( secured socket layer). Both are basically cryptographic protocols used mainly for internet transctions which requires security. Applications that use TLS are VoIP related application, email, IM’s and e-commerce applications.
TLS authenticates end points and after that we can have secured communication link between the end points between client and server. After succesful signing of between the client browser and the server we can do safe transaction and the procotol preclude our transactions from message tampering, message forgery and eavesdropping.
Below the state diagram which happen just before going to payment page.