This eBook explores how quantum computing is evolving from scientific theory into a practical engineering reality, and why its biggest long-term impact will be on modern cryptography. It explains how quantum concepts such as superposition, interference, and qubits differ from classical computing, then connects those ideas to the growing risk that sufficiently advanced quantum systems could eventually break widely used public-key encryption such as RSA and elliptic-curve cryptography.

Readers will gain a grounded understanding of why quantum risk matters now, especially because attackers can capture encrypted data today and decrypt it later once quantum capabilities mature. The eBook also outlines practical next steps for organizations, including cryptographic inventory, crypto-agility, PKI modernization, and hybrid post-quantum approaches such as PQ-TLS. Overall, it serves as a practical guide for security and IT leaders preparing their infrastructure, policies, and trust models for the post-quantum era.