There are (at least) two well-known operations in Elliptic-Curve Cryptography, namely
- Point Addition: One maps $(P, Q)\mapsto P + Q$, and
- Point Doubling: One maps $P\mapsto P + P = 2P$.
I'm interested in whether one can "undo" this second operation, meaning that given some $Q = 2P$, can one efficiently recover $P$?
