A cipher is a method of transforming plaintext (readable text) into ciphertext (encoded text) using an algorithm (set of rules). Ciphers are used for encryption, the process of converting plaintext into ciphertext, and decryption, the process of converting ciphertext back into plaintext.
Ciphers have been used for centuries to protect sensitive information from unauthorized access. Some of the most famous ciphers include the Caesar cipher, the Enigma machine, and the Data Encryption Standard (DES). Modern ciphers are typically implemented using computers and are much more complex than their historical counterparts. However, the basic principles of cipher design remain the same.
