http://y7yea4pmqqtznb33qiugvysyn2bob5v62e4pvoadoibrwkq3tsddjeyd.onion/my/glossary/man-in-the-middle-attack
When you first connected to Bahram, you actually connected to this person, and she, in turn, connected to Bahram. When you think you are asking Bahram a question, she receives your message, relays the question to Bahram, receives his answer back, and then sends it to you.