Length filter for list not working correctly

I am making a binary randomizing program that takes text in randomizes it and then output the randomized binary. But in the part that returns 7 digit binary objects to a list isn't working properly.

import random
message = input('What is your message? ')
def encrypter(message):
    shuffled = []
    second = []
    ascii,binary = [],[]
    for letter in message:
        ascii.append(ord(letter))
    for letter in ascii:
        binary.append(int(bin(letter)[2:]))
    print(binary)
    for character in binary:
        for digit in str(character):
            shuffled.append(digit)
    print(shuffled)
    random.shuffle(shuffled)
    print(shuffled)
    previous_number = 0
    current_string = ''
    for digit in shuffled:
        if len(current_string) < 7:
            current_string += digit
            previous_number = previous_number + 1 
        elif len(current_string) == 7:
            second.append(int(current_string))
            previous_number = 0
            current_string = ''

I tried changing the elif statement into an else statement but still no luck. It seems to not be able to read the length of the strings. I also tried to change it from checking the length of the string to using a counter like

number = previous_number+1
if number < 7:
    etc

To the best of my understanding, you want a chunked output of 7 digit numbers from the randomised binary representation of the input. This will do that. The length check was not failing, but you are resetting the output every time with current_string = '' so, even if you fixed it to return an output, you just keep throwing away the previous string.

Basically, I have just taken the chunking code from the canonical, and then I have added a list comprehension to join the digits back up from the chunked list.

import random

message = input('What is your message? ')

def encrypter(message, chunk_size=7):
    shuffled = []
    second = []
    ascii,binary = [],[]
    for letter in message:
        ascii.append(ord(letter))
    for letter in ascii:
        binary.append(int(bin(letter)[2:]))
    print(binary)
    for character in binary:
        for digit in str(character):
            shuffled.append(digit)
    print(shuffled)
    random.shuffle(shuffled)
    print(shuffled)
    
    chunked = [
        shuffled[i:i + chunk_size] for i in range(0, len(shuffled), chunk_size)
    ]
    joined = [''.join(item) for item in chunked]
    
    return joined
    
            
result = encrypter(message=message)
print(result)

If my interpretation is correct (and, well you're using random.shuffle() anyway) it should be noted that this is not "encryption" at all.