The aim of this thesis is to explore the McEliece cryptosystem, a post-quantum cryptosystem based on linear codes. As modern cryptosystems based on number theoretic problems, such as integer factorization and discrete logarithms, are no longer considered secure with the advent of quantum computers, there has been a shift towards the study and development of cryptosystems based on other difficult mathematical problems. The McEliece cryptosystem, based on the NP-hard general decoding problem of linear codes, is one such candidate. In this thesis, we provide a simplified explanation of the McEliece cryptosystem, using SageMath interactive codes to provide a hands-on experience with its basic working principles.