subCipher.py

import utils

PERMS = None


def decrypt(cipherText, key):
    return ''.join(list(map(key.get, cipherText)))


def genKey(key, keyGenType, itr):
    if keyGenType == 'manual':
        cipherWord = input("Enter an incorrect word from the plain text: ").upper()
        plainWord = input("Enter the correct word: ").upper()
        if len(cipherWord) != len(plainWord):
            print("Length of words must match! Key failed to update.")
            return key
        elif not (cipherWord.isalpha() and plainWord.isalpha()):
            print("Numbers can not be entered! Key failed to update.")
        else:
            cipherWordArray = []
            cipherWordArray[:0] = cipherWord
            plainWordArray = []
            plainWordArray[:0] = plainWord
            inverseKey = dict(zip(key.values(), key.keys()))
            for i in range(0, len(cipherWordArray)):
                if cipherWordArray[i] != plainWordArray[i]:
                    key[inverseKey[cipherWordArray[i]]] = plainWordArray[i]
                    key[inverseKey[plainWordArray[i]]] = cipherWordArray[i]
            print("Key updated! Try substitution cipher again.")
    elif keyGenType == 'auto':
        global PERMS
        if PERMS is None or itr == 0:
            PERMS = utils.permutations(key.values(), n=20, unique=True)
        key = dict(zip(key.keys(), PERMS[itr]))

    return key