Three people can keep a secret only if two of them are dead Benjamin Franklin Quotes such as these are very common. Keeping secret is not an easy task. In fact it is a human nature to share secrets to every other person. It is often said that to make something public, it should be called a secret. In early days of computing (1950s-60s), no importance was given on security, because the systems in those days were closed. In simple terms, computers exchange data and information with each other under the strict control of organizations. Even they are having their own protocols, not known to the public. Therefore, the chance of getting an access to the information was less possible. For that reason information security was not a major issue in those days. As the minicomputers and microcomputers evolved in the 1970s and 1980s, the issue of information security starting gaining attention. With the evolution of internet in 1990s, information security gained popularity. Numerous cases of information hacking, spoofing etc accelerates computer scientists to find new ways to make information exchange secure. On the other hand attackers also found new ways to attack the information. This process will continue to happen in the future. Therefore, it is very important for us to learn and invent new techniques to make data more secure, stored in the computer's hard disk or on move on the internet.