cipher

I build a cipher text = 'code with umer' custom_key = 'python'

def vigenere(message, key, direction=1): key_index = 0 alphabet = 'abcdefghijklmnopqrstuvwxyz' final_message = ''

for char in message.lower():

    # Append any non-letter character to the message
    if not char.isalpha():
        final_message += char
    else:        
        # Find the right key character to encode/decode
        key_char = key[key_index % len(key)]
        key_index += 1

        # Define the offset and the encrypted/decrypted letter
        offset = alphabet.index(key_char)
        index = alphabet.find(char)
        new_index = (index + offset*direction) % len(alphabet)
        final_message += alphabet[new_index]

return final_message

def encrypt(message, key): return vigenere(message, key)

def decrypt(message, key): return vigenere(message, key, -1)

print(f'\nEncrypted text: {text}') print(f'Key: {custom_key}') decryption = decrypt(text, custom_key) print(f'\nDecrypted text: {decryption}\n')