Definition: Encryption refers to the process of applying a special mathematical formula to a standard stream of data (text, special characters, audio, video) and converting the readable data into an "unreadable (or unusable) format". This is basically accomplished using using processing algorithms of varying strengths. The data stream or message (once encrypted) can be sent from one individual to another in a form that is indiscernible and then "translated" by the recipient using a pre-determined "key" to "unlock" the message. The deciphered message is then be displayed in its original format. The organization's information security policies should outline how and when the ciphering of messages and documents is to be used.
Its Relevance: Rendering data streams or messages unreadable, except for individuals with the appropriate key, is a very powerful information assurance tool. Encryption strongly supports maintaining the confidentiality of sensitive information. Encrypted data is very hard to "break". It's important that every organization have an policies addressing the use of encryption.