TypeError: 'int' object has no attribute '__getitem__'?

Question

Python

Hello!
In general, I need to store the record for the game in a separate text file. The record is encrypted using PyCrypto.
Wrote this script:

# -*- coding: utf-8 -*-
import sys
import hashlib
from Crypto.Cipher import AES

password = "catchfugitive"
key = hashlib.sha256(password).digest()
iv = 16 * '\x00' # Initialization vector
mode = AES.MODE_CBC
time_score = 45

def decryption(key, mode, iv, record):
  """
    Decrypt record from file.
    Thanks a lot for PyCrypto.
  """
  decryptor = AES.new(key, mode, iv)
  record[0] = decryptor.decrypt(str(record[0]))
  return record

def encryption(key, mode, iv, record):
  """
    Encrypt record to file.
      Thanks a lot for PyCrypto.
  """
  encryptor = AES.new(key, mode, iv)
  record[0] = encryptor.encrypt(record[0])
  return record

try:
  record_file = open("../statistics/record.txt", "r")
except:
  sys.exit()
    
record = [line.strip() for line in record_file]
print(record[0])
    
if int(record[0]) < time_score:
  record[0] = time_score

record_file.close()

try:
  record_file = open("../statistics/record.txt", "w")
except:
  sys.exit()
record[0] = encryption(key, mode, iv, record[0])

for index in record:
  record_file.write(str(index) + "\n")

record_file.close()

But when I run it, I get the following error:
Traceback (most recent call last):
File "script.py", line 47, in
record[0] = encryption(key, mode, iv, record[0])
File "script.py" , line 27, in encryption
record[0] = encryptor.encrypt(record[0])
TypeError: 'int' object has no attribute '__getitem__'
How to deal with this? Please, help.