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Caesar Cipher
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.. tags:: short, beginner, cryptography, math


The Caesar cipher is an ancient encryption algorithm used by Julius Caesar. It
encrypts letters by shifting them over by a certain number of places in the
alphabet. We call the length of shift the key. For example, if the key is 3,
then A becomes D, B becomes E, C becomes F, and so on. To decrypt the message,
you must shift the encrypted letters in the opposite direction. This program
lets the user encrypt and decrypt messages according to this algorithm.

In modern times, the Caesar cipher isn’t very sophisticated, but that makes it
ideal for beginners. The program in Project 7, “Caesar Hacker,” can brute-force
through all 26 possible keys to decrypt messages, even if you don’t know the
original key. Also, if you encrypt the message with the key 13, the Caesar
cipher becomes identical to Project 61, “ROT 13 Cipher.” Learn more about the
Caesar cipher at https://en.wikipedia.org/wiki/Caesar_cipher


.. collapse:: caesar_cipher.py

   .. literalinclude:: caesar_cipher.py
      :language: python
      :linenos:


https://inventwithpython.com/bigbookpython/project6.html