import os

read_path = os.path.join(os.getcwd(), 'task5_data.txt')
write_path = os.path.join(os.getcwd(), 'task5_data_new.txt')

if not os.access(read_path, os.R_OK):
    print('Файл "{}" не доступен для чтения'.format(read_path))
elif not os.access(write_path, os.W_OK):
    print('Файл "{}" не доступен для записи'.format(write_path))

else:
    with open(read_path) as f:
        print(f.read())

    with open('task5_data.txt', 'rb') as input_byte, open(write_path, 'wb') as out:
        char = input_byte.read(1)
        while char:
            number = int(char.hex(), 16)
            out.write(bytes([number ^ 2]))
            char = input_byte.read(1)