Data or file encryption is the application of a cryptographic algorithm to the data or file so that when it's stored or transmitted, only those users or addressees with the appropriate access can open, execute, or apply its contents. Encryption and cryptography are expansive terms that cover a variety of approaches, applications, and methods to securing data and file assets. For the remainder of this discussion, we'll use the term encryption to cover data conversion through the application of cryptography.
At its most basic levels, encryption has three primary objectives—confidentiality, integrity, and availability (CIA). In addition, the CIA triad is usually extended to include authentication, authorization, and non-repudiation. Encryption is a data integrity and confidentiality protection mechanism.