To be sure that these pages are indeed protected by SSL, you can also check the site's URL, which must begin https://, the 's' indicating that this security system is in force.
You have noticed a padlock icon at the bottom of certain web pages. It indicates that the page uses the SSL protocol (a data transfer security standard that encrypts data and authenticates the server and the integrity of the message) or the TLS protocol. This symbol indicates that all information, most notably banking details, is secured.
SSL stands for Secure Sockets Layers, a common way of securing Internet communications. SSL is used to encrypt data, authenticate the server and verify the integrity of messages. When data is transmitted using SSL, it enters a kind of tunnel that makes the information invisible to anyone other than the target for the data exchange. SSL is rapidly being superceded by https, which is now a safer way to shop and pay online. (See also, How does Internet security work?)