Plaintext is a term with several meanings.


Plain text can refer to computer files in ASCII or other human-readable form. This usually excludes files stored with formatting, such as Microsoft Word files, but includes any file that can be opened, read, and edited with a text editor such as Notepad (on Microsoft Windows), pico, nano, vi, emacs (on UNIX), SimpleText (on Mac OS), or TextEdit (on Mac OS X). Most programming languages require source files to be stored in plain text, as do HTML and XML.


Plaintext is the input to a crypto system, or more simply, the message that will be encrypted.

In any crypto system, plaintext must be handled properly lest an attacker gain considerable advantage.