understand what the original plaintext was just by looking at the ciphertext here is the previous example encrypted into ciphertextyvccf kyvivkyv bvpj kf kyv yfljv riv yzuuve leuvi kyv wcfnvi gfk but if you know about the cipher used to encrypt the messageyou can decrypt the ciphertext back to the plaintext (decryption is the opposite of encryption many ciphers also use keys keys are secret values that let you decrypt ciphertext that was encrypted using specific cipher think of the cipher as being like door lock you can only unlock it with particular key if you are interested in writing cryptography programsyou can read my other book"hacking secret ciphers with pythonit is free to download from the caesar cipher the key for the caesar cipher will be number from to unless you know the key (that isknow the number used to encrypt the message)you won' be able to decrypt the secret code the caesar cipher was one of the earliest ciphers ever invented in this cipheryou encrypt message by taking each letter in the message (in cryptographythese letters are called symbols because they can be lettersnumbersor any other signand replacing it with "shiftedletter if you shift the letter by one spaceyou get the letter if you shift the letter by two spacesyou get the letter figure - is picture of some letters shifted over by three spaces figure - shifting over letters by three spaces hereb becomes to get each shifted letterdraw out row of boxes with each letter of the alphabet then draw second row of boxes under itbut start certain number (this number is the keyof spaces over after the letters at the endwrap around back to the start of the boxes here is an example with the letters shifted by three spacespost questions to