# Terminology

## Cryptography

* Art or science of hidden writing
  * from Gr. _kryptós_, hidden + _graph_, r. of _graphien_, to write
* It was initially used to maintain the confidentiality of information.
* **Steganography**
  * from Gr. _steganós_, hidden + _graph_, r. of _graphien_, to write

## Cryptanalysis

* Art of science of breaking cryptographic systems or encrypted information.

## Cryptology

* Cryptography + cryptanalysis

## Cipher

* Specific cryptographic technique.

### Operation

* **Encryption**: plaintext (or cleartext) -> ciphertext (or cryptogram).
* **Decryption**: ciphertext -> plaintext
* **Algorithm**: way of transforming data.
* **Key**: algorithm parameter

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