Category: misc
Points: 493 (15 solves)
Challenge Description
I want to check if any of my passwords have been stolen, but I don't want to risk sending them to Have I Been Pwned. I want a stronger guarantee than the k-anonymity that they provide. You can help me by submitting any leaked passwords you may find to a private set intersection protocol.
Usage: ./psi_sender.py password1234 notthepassword fall2021
Solution
In this challenge we are supposed to find all passwords in a private set intersection protocol from this paper. The exact workings of the protocol are not terribly important since we exploit the fact that the polynomials are related.