A cipher may refer to any of the following:

  1. A cipher is an algorithm that encodes or encrypts data. Text that is “ciphered” (processed with a cipher, encrypted) cannot be read unless the original algorithm is known or reasoned out. In cryptographic ciphers, a special password or key must be provided to the decryption algorithm before the text can be deciphered.

  2. Windows command line command. See the cipher command page for additional details and examples.

  • How to password protect files and folders in Windows.
  • Computer security help and support.

Security terms