This paper introduces a novel adaptation of the Niederreiter cryptosystem that integrates a hybrid model of Goppa and Low-Density Parity-Check (LDPC) codes to enhance the Classic McEliece cryptosystem. The method uses parity-check matrices for encoding within the Niederreiter framework, combining the strong error correction of Goppa codes with the efficiency of LDPC codes. Encoding is performed in two stages: first, Goppa encoding on smaller blocks, followed by LDPC encoding over the entire message, ensuring smooth integration and compatibility. A hybrid parity-check matrix, formed by multiplying the LDPC and scaled Goppa matrices, merges their complementary strengths while naturally meeting the weight constraints necessary for secure Niederreiter encryption. Importantly, this entire LDPC-based Niederreiter scheme is wrapped within the Classic McEliece Key Encapsulation Mechanism (KEM), which provides an additional layer of security and ensures IND-CCA2 robustness. This combined approach significantly reduces key sizes, approximately thirty-six times smaller than Classic McEliece, while maintaining strong theoretical security.