import json
import base64
import cryptography

# The decription function

data = str(base64.urlsafe_b64decode("NDksNiBZSQ=="), "utf-8")
print(data)

encrypted2 = ''

i = len(data) - 1

while i >= 0:
    encrypted2 = encrypted2 + data[i]
    i = i - 1

encrypted2 =str(encrypted2)
print(encrypted2)




def cipher_decrypt(ciphertext, key):

    decrypted = ""

    for c in ciphertext:

        if c.isupper(): 

            c_index = ord(c) - ord('A')

            # shift the current character to left by key positions to get its original position
            c_og_pos = (c_index - key) % 26 + ord('A')

            c_og = chr(c_og_pos)

            decrypted += c_og

        elif c.islower(): 

            c_index = ord(c) - ord('a') 

            c_og_pos = (c_index - key) % 26 + ord('a')

            c_og = chr(c_og_pos)

            decrypted += c_og

        elif c.isdigit():

            # if it's a number,shift its actual value 
            c_og = (int(c) - key) % 10

            decrypted += str(c_og)

        else:

            # if its neither alphabetical nor a number, just leave it like that
            decrypted += c

    return decrypted
    
decrypted_message = cipher_decrypt(encrypted2, 4)
print(decrypted_message)
decodedBytes = base64.urlsafe_b64encode(decrypted_message.encode("utf-8"))
p_decoded = str(decodedBytes, "utf-8")
print(p_decoded)

data_decoded = str(base64.urlsafe_b64decode(p_decoded), "utf-8")
print(data_decoded)