Mapping Quantum Threats: An Engineering Inventory of Cryptographic Dependencies

The prospective emergence of large-scale quantum computers capable of executing Shor's algorithm at cryptographically relevant scale would render widely deployed public-key cryptography computationally insecure. Under this threat model, both confidentiality of previously protected data and the authenticity of digital signatures could be compromised across multiple layers of digital infrastructure. This paper presents a systematic engineering inventory of technologies that depend on quantum-vulnerable asymmetric cryptography. The analysis is structured along two complementary axes (technology domain and operational environment) linking cryptographic primitives to their real-world deployment contexts. The resulting framework provides a structured basis for identifying systemic exposure to quantum-related risks across contemporary digital ecosystems.