Function encrypt

ciphers/caesar_cipher.py:6–88

encrypt ======= Encodes a given string with the caesar cipher and returns the encoded message Parameters: ----------- * `input_string`: the plain-text that needs to be encoded * `key`: the number of letters to shift the message by Optional: * `alph

(input_string: str, key: int, alphabet: str | None = None)

def encrypt(input_string: str, key: int, alphabet: str | None = None) -> str:
    """
    encrypt
    =======

    Encodes a given string with the caesar cipher and returns the encoded
    message

    Parameters:
    -----------

    *   `input_string`: the plain-text that needs to be encoded
    *   `key`: the number of letters to shift the message by

    Optional:

    *   `alphabet` (``None``): the alphabet used to encode the cipher, if not
        specified, the standard english alphabet with upper and lowercase
        letters is used

    Returns:

    *   A string containing the encoded cipher-text

    More on the caesar cipher
    =========================

    The caesar cipher is named after Julius Caesar who used it when sending
    secret military messages to his troops. This is a simple substitution cipher
    where every character in the plain-text is shifted by a certain number known
    as the "key" or "shift".

    Example:
    Say we have the following message:
    ``Hello, captain``

    And our alphabet is made up of lower and uppercase letters:
    ``abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ``

    And our shift is ``2``

    We can then encode the message, one letter at a time. ``H`` would become ``J``,
    since ``J`` is two letters away, and so on. If the shift is ever too large, or
    our letter is at the end of the alphabet, we just start at the beginning
    (``Z`` would shift to ``a`` then ``b`` and so on).

    Our final message would be ``Jgnnq, ecrvckp``

    Further reading
    ===============

    *   https://en.m.wikipedia.org/wiki/Caesar_cipher

    Doctests
    ========

    >>> encrypt('The quick brown fox jumps over the lazy dog', 8)
    'bpm yCqks jzwEv nwF rCuxA wDmz Bpm tiHG lwo'