This paper presents a strong (k, n) threshold-based ramp secret sharing scheme with k access levels. The secrets are the elements represented in a square matrix S. The secret matrix S can be shared among n different participants using a matrix projection technique where: i) any subset of k participants can collaborate together to reconstruct the secret, and ii) any subset of (k - 1) or fewer participants cannot partially discover the secret matrix. The primary advantages are its large compression rate on the size of the shares and its strong protection of the secrets.