The Caesar cipher is one example of a larger class of techniques called substitution ciphers. These replace every letter in a message with something else according to a translation.

The first paragraph gave the key of the code ("The word “words” appears 6 times in the paragraph, 6 is the key to decrypt these clues using the good old Caesar Shift Cipher.") ...

Caesar used a substitution cipher, where each letter of the alphabet was replaced by a letter in a different fixed position further up or down in the alphabet.

J K Rowling’s The Hallmarked Man features the Pigpen Cipher, a centuries-old code once used by Freemasons and revolutionaries ...

Challenge 3 Julius Caesar However, as ciphertext is used to send a secret message to the military, decryption was being actively done in the days of the Roman Empire.