Analyzing this code, I see that it takes my input and looks for all instances of “suzuki_harumiya” and removes it. Then it compares the resulting string to “suzuki_harumiya”. If it is true, then it runs the “open_up()” function.
I see that I can simply manipulate my input to “ssuzuki_harumiyauzuki_harumiya” and the script will remove the single instance of “suzuki_harumiya” in it and the resulting string will, in fact, be “suzuki_harumiya”. When I feed that input, I get this:
A quick Google search tells me that Reddit is the front page of the internet, so I search for entries related to vishwactf on reddit:
I see that there is a comment indicating that another comment has been deleted:
AI hop in my time machine at Archive.org and go down memory lane:
I now have what appears to be a ciphered flag with a clue. The part about the “18th century French scholars” tells me to try decrypting it as a Vigenere cipher. I head over to dcode.fr and try it out. The automatic decryption failed, so after some contemplating, I try “VISHWACTF” as the key and I get the flag: