Seems the base64 module has issues with bad file(s). This does not seems to generate a Crash Report.

t:~$ python3 -m base64 -d "12s345a2"
Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/lib/python3.6/base64.py", line 602, in <module>
    main()
  File "/usr/lib/python3.6/base64.py", line 585, in main
    with open(args[0], 'rb') as f:
FileNotFoundError: [Errno 2] No such file or directory: '12s345a2'

test@TestNut:~$ python3 -m base64 -d /test.txt
Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/lib/python3.6/base64.py", line 602, in <module>
    main()
  File "/usr/lib/python3.6/base64.py", line 585, in main
    with open(args[0], 'rb') as f:
FileNotFoundError: [Errno 2] No such file or directory: '/test.txt'