The Hidden Threat: Harvest-Now-Forge-Later and the Collapse of Digital Trust

The timelines for post-quantum cryptography are tightening, and the real threat surface extends far beyond decrypting old data. In this episode of Shielded: The Last Line of Cyber Defense, host Jo Lintzen speaks with Konstantinos Karagiannis, Director of Quantum Computing Services at Protiviti and host of The Post-Quantum World podcast, about the attacker’s perspective on quantum risk and why the world must plan for more than harvest-now-decrypt-later. Konstantinos explains why harvest-now-forge-later attacks on code signing, software supply chains, and blockchain consensus represent the most powerful quantum-enabled vectors, and how the emerging five-day rule for breaking RSA-2048 reshapes threat modeling and urgency. Expect practical direction on identifying crown jewels, demanding vendor clarity, building crypto inventory, and framing post-quantum migration as a core cyber resilience priority rather than a future experiment.