Plaintext

In cryptography, plaintext is information a sender wishes to transmit to a receiver. Cleartext is often used as a synonym. Plaintext has reference to the operation of cryptographic algorithms, usually encryption algorithms, and is the input upon which they operate. Cleartext, by contrast, refers to data that is transmitted or stored unencrypted (that is, 'in the clear').

Overview

Before the computer era, plaintext most commonly meant message text in the language of the communicating parties. Since computers became commonly available, the definition has expanded to include:

Much of this data is not directly meaningful to humans, being already transformed into computer manipulable forms. While the original definition implied that the message could be read by a human being, the modern definition emphasizes that a person using a computer could easily interpret the data.