https://2019.www.torproject.org/docs/faq.html.en#AttacksOnOn... It's not 100%, but the more of the connection your attacker can see, the worse your odds. If you're in the USA and you're using nodes in the Five Eyes https://en.wikipedia.org/wiki/Five_Eyes and you're being tracked by the NSA, they might be able to see everything. Maybe. Also check point #4 on this answer https://2019.www.torproject.org/docs/faq.html.en#EverybodyAR...