caesar_cipher

"""
Caesar cipher - Implement a Caesar cipher, both encoding and decoding. 
The key is an integer from 1 to 25. This cipher rotates the letters of the alphabet (A to Z). The encoding replaces each letter
with the 1st to 25th next letter in the alphabet (wrapping Z to A). So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" 
to "BC". This simple "monoalphabetic substitution cipher" provides almost no security, because an attacker who has the encoded 
message can either use frequency analysis to guess the key, or just try all 25 keys.

Time to implement: 1 hour
"""

from langdetect import detect


def cleanup(message):
    PUNC = "!?.#@$%^&*()"
    message = message.lower()

    final = ""
    for i in message:
        final = final + i.strip(PUNC)

    return final


def caesar_cipher(cipher_type, message, encode=True):
    ALPHABET = "abcdefghijklmnopqrstuvwxyz"
    message = cleanup(message)
    start = ALPHABET.find(cipher_type)
    ciph_letters = ALPHABET[start:] + ALPHABET[:start]
    translated = ""

    if encode == True:
        output, input = ciph_letters, ALPHABET
    else:
        output, input = ALPHABET, ciph_letters

    for letter in message:
        if letter == " ":
            translated = translated + letter
        else:
            translated = translated + output[input.find(letter)]

    return translated


x = caesar_cipher("g", "Procrastination is awesome!")
print(x)


def decipher(message):
    ALPHABET = "abcdefghijklmnopqrstuvwxyz"

    for letter in ALPHABET:
        translated = caesar_cipher(letter, message, encode=False)
        if detect(translated) == "en":
            return translated, letter

    return "Cannot be translated to English"


print(decipher(x))