Learn String Manipulation by Building a Cipher - Step 80

Python
1

Tell us what’s happening:

Can anyone please tell me how the outputs of encryption and decryption are same? The encryption output is clear to me but I can’t understand the decryption output. Both are showing ‘helloozairax’.
I will appreciate your help in this situation.

Your code so far

text = 'Hello Zaira!'
custom_key = 'python'

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

    for char in message.lower():

# User Editable Region

        # Append space to the message
        if char.isalpha():
            final_message += char

# User Editable Region

        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
    
encryption = vigenere(text, custom_key)
print(encryption)
decryption = vigenere(encryption, custom_key, -1)
print(decryption)

Your browser information:

User Agent is: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Mobile Safari/537.36

Challenge Information:

Learn String Manipulation by Building a Cipher - Step 81

2

that is going to change once you follow the instructions in this step

1 Like