Encryption is the act of transforming a plaintext into a ciphertext. The opposite process is decryption.

Let `K`

be a set of keys, `M`

be a of plaintext messages, and
`C`

be a set of ciphertext messages.
The bijection `E`

, where _{k}:M→C`k∈K`

,
is an encryption function or encryption transformation.

L. R. Knudsen, M. J. B. Robshaw, *The Block Cipher Companion.* Springer, 2011.

Copyright © 2014 Barry Watson. All rights reserved.