Integrity of digital security is crucial for maintaining the secrecy of banking data, personal information, company trade secrets, governmental records, and more. A perfectly implemented quantum cryptographic scheme, such as quantum key distribution (QKD), would be impossible to break. Freespace QKD systems commonly rely on polarization encoded single-photons. However, the optics required to manipulate photons can perturb the polarization, reducing the encoded state’s integrity thus, decreasing the quality of the quantum channel. Here I present a method for characterizing the effects of optical elements on photon polarization with respect to QKD performance. This computational model describes polarization effects by tracing light propagation paths through many individual optical elements. This research will forward for the development of freespace QKD reliability.