Encryption is the transformation of information into a form that is only readable by those with the particular technology and un-encryption knowledge, to prevent others who might have access to the information from reading it. It has long been used for messages in transit, whether carried by hand, transmitted via radio or sent over a computer network - if the messages were intercepted, the interceptor would be unable to interpret the information. It also serves an important role for stored information to protect it in case of loss or theft.
While the concepts and processes of encryption greatly pre-date modern computing, the topic has become increasingly popular in computing over the past few years. This has largely been fuelled by the vast increase of information transferred over computer networks and Internet, and due to the increased security concerns that accompany a massively interconnected "always online" computing environment.