The process of converting information into a coded form so that only authorized parties holding the key can read it.
Encryption transforms readable data into ciphertext using an algorithm and a key, so that anyone without the key sees only scrambled output. It protects data at rest, such as on disks and backups, and data in transit, such as over networks.
It is a primary control for confidentiality and, with the right schemes, for integrity. Effective encryption depends as much on strong key management as on the algorithm itself.