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Cybersecurity StrategyOctober 16, 2025·6 min read

Quantum Computing and Cybersecurity: What Mid-Market Organizations Need to Know Now

Quantum computing is an emerging risk that organizations need to begin planning for today — not because quantum-capable computers are widely available, but because the preparation window is shorter than most realize.

Quantum computing is no longer a distant research topic. It's an emerging risk that organizations need to begin planning for today — not because quantum computers capable of breaking current encryption are widely available, but because the window to prepare is shorter than most organizations realize.

The core problem is sometimes called "harvest now, decrypt later." Sophisticated adversaries — particularly nation-state actors — are intercepting and storing encrypted data today with the expectation of decrypting it once quantum computing matures. For organizations that handle sensitive data with long-term confidentiality requirements — healthcare records, legal matter files, financial data — this is an active risk, not a future one.

What Quantum Computing Actually Threatens

Current public-key cryptography — RSA, ECC, and similar algorithms — relies on mathematical problems that classical computers cannot solve in practical timeframes. Quantum computers, using algorithms like Shor's algorithm, can solve these problems efficiently. This means the cryptographic foundation underlying most secure communications, digital signatures, and data protection could be compromised as quantum computing scales.

Symmetric encryption (AES-256, for example) is less immediately threatened but still warrants attention. The practical timeline for cryptographically relevant quantum computing is uncertain — estimates from serious researchers range from five to fifteen years — but the preparation timeline for large organizations is measured in years, not months.

Post-Quantum Cryptography

The response to quantum risk is post-quantum cryptography (PQC): cryptographic algorithms designed to resist attacks from both classical and quantum computers. NIST completed its first post-quantum cryptography standardization process in 2024, publishing standards for four algorithms. Organizations should begin evaluating these standards against their current cryptographic infrastructure.

The transition to post-quantum cryptography is not a simple software update. It requires a full cryptographic inventory — understanding what encryption is in use, where, and for what purpose — followed by a prioritized migration plan.

What Organizations Should Do Now

Build a cryptographic inventory: Identify what cryptographic algorithms are in use across your environment, including vendor and third-party systems. This is the prerequisite for any meaningful quantum risk planning.

Assess data sensitivity and longevity: Prioritize protection for data that needs to remain confidential for ten or more years. That data is most at risk from harvest-now-decrypt-later tactics.

Monitor NIST standards: NIST's post-quantum cryptography standards are published and evolving. Ensure your security program and vendor relationships are tracking these developments.

Engage your vendors: Most quantum risk exposure comes through third-party systems. Begin asking your critical vendors — particularly cloud providers, communication platforms, and identity systems — about their post-quantum cryptography roadmaps.

The Role of Security Leadership

Quantum risk planning is a security leadership function. CISOs and vCISOs should be tracking NIST standards, engaging with legal and compliance on data longevity requirements, and ensuring that quantum risk is represented in the organization's risk register — even if the mitigation timeline extends beyond the current planning horizon.

The organizations that will navigate the post-quantum transition most effectively are those that start building inventory and awareness now, before the timeline becomes urgent.

About the author
Branden Rowe, Founder and Managing Director of Antares Security

Branden Rowe

Founder & Managing Director, Antares Security

Branden Rowe is the Founder and Managing Director of Antares Security, a cybersecurity advisory practice focused on governance, operational security, risk management, and executive-level security leadership. His career spans security and risk leadership across regulated and enterprise environments including Northern Trust, Baker Tilly, Wolters Kluwer, and Cushman & Wakefield.

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