부산대학교 도서관

Communication over the Internet is an integral part of the connected world. As the Internet is a public network, the data packets exchanged by the communicating parties pass through various insecure channels and untrusted servers before they reach their destinations. Still, we feel it is safe to send e-mails, visit social media websites, watch movies of our own preferences online, and shop online using credit cards. Cryptography or encryption makes it possible to protect our private information in the presence of third parties. When we browse a secured website, we see a lock symbol on the browser; it means our communication with the website is encrypted, and hence, no third party will be able to read the data packets exchanged between the browser and the website. Hypertext Transfer Protocol Secure (HTTPS) is used to establish an encrypted, hence secured communication channel between a web browser and a website. The browser website is just one example; cryptography is happening in your mobile phones, smart cards, IoT devices, and in almost all connected devices.