tl;dr1. Find Elliptic Curve parameters from given points on the curve2. Find x-coordinate of 2\*P, given y-coordinate of 2\*P3. Invert 2 over mod (P.order()) and multiply the result with 2\*P to get P4. Submit ASIS{P.x} as the flag
Full write-up: [https://blog.bi0s.in/2019/04/23/Crypto/Elliptic-Curves/asis-quals19-halloween-party/](https://blog.bi0s.in/2019/04/23/Crypto/Elliptic-Curves/asis-quals19-halloween-party/)