The attached file looks like a utf-16 encoded mess. But, in fact it isn’t. The script below is self-explaining.
Workflow is as below:
- drop all the non-printable characters
- base58 decode the payload
- base64 decode the payload
- replace all ‘I’ and ‘l’ with ‘0’ and ‘1’
- read the payload as binary written string
- get the flag 😉