MAT247

uoftctf2026

Task: Distinguish between matrix powers A^k and random commuting polynomials p(A) over GF(p) for a 12x12 matrix, encoding 368 flag bits. Solution: Used a determinant subgroup membership test: det(A^k) always lies in the cyclic subgroup generated by det(A), while random polynomials produce determinants outside this subgroup with probability 17/18, then applied error correction for ~5.5% false positives.