Шифр XOR для любого типа файла

#Ввод ключа
key = input("Key = ")
#key = "littleKey"
str1 = ""
#Чтение текста из файла
with open("input1.txt", "r", encoding="utf8") as file:
    for line in file:
        str1 += line
print(str1)
str2 = ''
for i in range(len(str1)):
    x = ord(str1[i])
    count = len(key)
    y = ord(key[i % count])
    #XOR шифрование
    z = x ^ y
    str2 += chr(z)
#Запись зашифрованной строки в новый файл
with open("output1.txt", "w", encoding="utf8") as file:
    file.write(str2)
print("Encode = ", str2)
#Такой же процесс, но расшифрование
str3 = ''
for i in range(len(str2)):
    x = ord(str2[i])
    count = len(key)
    y = ord(key[i % count])
    z = x ^ y
    str3 += chr(z)
with open("output3.txt", "w", encoding="utf8") as file:
    file.write(str3)
print("Dencode = ", str3)

#key = input("Key = ")
key = "littleKey"
str1 = bytearray()
f = open("input1.txt", "rb")
f2 = open("output1.txt", "wb")
while True:
    b = f.read(1)
    if b == b'':
        break
    str1 += b
print(str1)
f.close()
str2 = bytearray()
for i in range(len(str1)):
    x = str1[i]
    count = len(key)
    y = ord(key[i % count])
    z = x ^ y
    str2 += z
f2.write(str2.encode('utf-8'))
f2.close()
print("Encode = ", str2)

key = b'littlekey'
 
with open('1.txt', 'rb') as file:
    source = file.read()
    
print(source)
print('='*30)
 
encrypted = bytearray()
count = len(key)
for idx, x in enumerate(source):
    encrypted.append(x ^ key[idx % count])
source = bytes(encrypted)
 
with open('2.txt', 'wb') as file:
    file.write(source)
 
 
with open('2.txt', 'rb') as file:
    source = file.read()
    
print(source)
print('='*30)
 
encrypted = bytearray()
for idx, x in enumerate(source):
    encrypted.append(x ^ key[idx % count])
source = bytes(encrypted)
 
with open('3.txt', 'wb') as file:
    file.write(source)
    
print(source)