Security Encyclopedia


Ciphertext is what encryption algorithms, or ciphers, transform an original message into.

Data is said to be encrypted when a person or device lacking the cipher is unable to read it. They, or it, would need the cipher to decrypt the information.

Algorithms transform plaintext into ciphertext, and ciphertext into plaintext. These respective processes are called encryption and decryption.

Examples of different ciphers are as follows:

  • Caesar Cipher
  • Mono Alphabetic Cipher
  • Homophonic Substitution Cipher
  • Polygram Substitution Cipher
  • Vigenere Cipher
  • Transposition Techniques
    • Rail Fencing
    • Simple Columnar Transposition
    • Vernam Cipher

History's first recorded device to encipher communications dates back to 400 BC. Ancient Greeks secured military communications between central and field leadership using a device called a scytale. The device consisted of a baton of specific proportions with a spiral of parchment with a written message. If unwrapped the message was beyond comprehension, but if wrapped around a baton of exact proportions, it was legible and intelligible.


"An unauthorized party to a conversation, even if they intercept our messages, would only possess ciphertext . Without the encryption algorithm and key they'd never have it in plaintext."