HSCTF_2017:

Category: Crypto Points: 100 Description:

Alice is sending a top secret polynomial, P(x), to Bob. You want to know the equation of P(x). In your attempts to intercept their message, you discover only two facts about P(x): It’s coefficients are in the set {0, 1, 2, …, 1000}. P(2017) = 49189926321482294101673925793095 The flag will be P(1).

Write-up

Create a Python to solve it for you

Solution

Therefore, the flag is 231.