In this challenge the flag is treated as a polynomial over GF(257), it is blinded by a random known polynomial, and then it is evaluated at 107 first integers. However, each result is corrupted with probability 43/108. The polynomial has degree 25, so we need 26 correct points to interpolate it. Observe that by choosing random 26 points from those given, we have a feasible probability of having an error-less set:
sage: math.log(binomial(108-43, 26) / binomial(108, 26), 2) -22.716429556377932
That is, we need to try around 7 000 000 random subsets. This can be done in 10 minutes on 8 cores by a simple Sage code.