Quantum Computing Threats: RSA & AES Still Safe

·

Quantum computing threats to modern encryption have sparked widespread concern—but how real are they? This comprehensive analysis examines when quantum computers could realistically break RSA-2048 and AES-256, evaluates the progress of post-quantum cryptography (PQC), and outlines actionable strategies to safeguard data today. While breakthroughs from IBM, Google, Microsoft, and D-Wave continue to advance quantum capabilities, current encryption standards remain resilient for the foreseeable future.

Core keywords: quantum computing threats, RSA-2048, AES-256, post-quantum cryptography, Shor’s algorithm, Grover’s algorithm, segmented key encryption, NIST PQC

The Reality of Quantum Threats in 2025

Despite growing headlines, quantum computers pose no immediate danger to widely used encryption like RSA-2048 or AES-256. In October 2024, D-Wave’s quantum computer successfully factored a 22-bit RSA key—a technical milestone but far from threatening real-world systems. Breaking RSA-2048 would require approximately 20 million stable qubits operating coherently for hours, a threshold decades away.

Experts estimate RSA-2048 won’t be at risk until at least 2035–2040, with some projections extending to 2055–2060. Even RSA-3072 and RSA-4096 offer significantly extended lifespans against future quantum attacks. Meanwhile, AES-256 remains highly secure due to its resistance to quantum brute-force methods.

Key Takeaways:

  • RSA-2048 & AES-256 remain secure through at least 2035
  • Grover’s algorithm reduces AES-256 security to 128-bit—still infeasible
  • Shor’s algorithm requires ~20 million qubits to break RSA-2048
  • NIST’s HQC draft standard expected in 2025, final by 2027
  • Segmented key encryption enhances quantum resilience immediately

Shor’s Algorithm vs. RSA: Why 20 Million Qubits Are Needed

The primary quantum threat to RSA comes from Shor’s algorithm, which efficiently factors large integers—a task classical computers struggle with. However, running Shor’s algorithm on RSA-2048 demands massive quantum resources.

According to research by Craig Gidney and Martin Ekerå, breaking RSA-2048 would require around 20 million noisy physical qubits sustained for eight hours. This accounts for error correction: each logical qubit may need thousands of physical qubits to maintain stability.

Current systems fall far short:

Only universal gate-based quantum computers can run Shor’s algorithm. D-Wave’s machines use quantum annealing, suitable for optimization but not cryptographic factorization.

👉 Discover how next-gen encryption can outpace quantum threats before they emerge.

Grover’s Algorithm and AES-256: A Manageable Challenge

Unlike RSA, AES-256 is symmetric encryption and resists Shor’s algorithm entirely. The main quantum threat comes from Grover’s algorithm, which can theoretically halve the effective security of a symmetric key.

For AES-256, this reduces security from 2²⁵⁶ to 2¹²⁸ operations—still computationally infeasible. No known quantum architecture can perform that many operations within a practical timeframe.

Moreover, AES uses a substitution-permutation network (SPN), which produces no exploitable algebraic structures like "syzygies" found in code-based cryptosystems such as McEliece. This makes AES inherently more resistant to mathematical attacks.

FAQ: Common Questions About Quantum Threats

Q: Can quantum computers break AES-256 today?
A: No. Even with Grover’s algorithm, breaking AES-256 requires 2¹²⁸ operations—beyond the capability of any existing or near-future quantum system.

Q: When will RSA-2048 be broken by quantum computers?
A: Not before 2035–2040 at the earliest. Most experts project it could take until 2055–2060 due to engineering challenges in scaling stable qubits.

Q: What is the difference between logical and physical qubits?
A: Logical qubits are error-corrected and stable; physical qubits are prone to noise. Thousands of physical qubits may be needed to create one reliable logical qubit.

Q: Is post-quantum cryptography ready for deployment?
A: Partially. NIST has standardized Kyber (ML-KEM) and selected HQC for draft status in March 2025, with full standards expected by 2027.

Q: Does segmented key encryption really help against quantum attacks?
A: Yes. By splitting keys into independently encrypted segments, it multiplies the difficulty of brute-force attacks—even for quantum computers.

Q: Are all quantum computers equally dangerous to encryption?
A: No. Only universal gate-model quantum computers (like IBM and Google’s) can run Shor’s algorithm. D-Wave’s annealers cannot break RSA or AES.

Post-Quantum Cryptography: NIST’s Roadmap and Global Adoption

The National Institute of Standards and Technology (NIST) is leading the global transition to PQC. As of 2025:

HQC offers strong resistance using code-based cryptography, though recent research—like Hugues Randriambololona’s “syzygy distinguisher” (Best Paper at Eurocrypt 2025)—has identified potential weaknesses in certain McEliece variants. These findings reinforce the need for diverse cryptographic approaches.

Segmented Key Encryption: Immediate Quantum Resilience

While PQC adoption grows, segmented key encryption provides an immediate defense layer. Developed by Jacques Gascuel of Freemindtronic, this patented method divides encryption keys into multiple independently encrypted segments.

For example:

Even if a quantum computer cracks one segment, reconstructing the full key remains nearly impossible without access to the others. This approach strengthens both RSA and AES implementations against classical and quantum brute-force attacks.

👉 Explore how segmented key technology creates unbreakable layers of encryption today.

China’s Quantum Strategy vs. Decentralized Security

China leads in real-world deployment of quantum-safe systems. In May 2025, China Telecom Quantum Group launched a hybrid encryption network combining Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC) across 16 cities.

The system supports:

However, this model relies on centralized infrastructure subject to state oversight under China’s Data Security Law (DSL) and Personal Information Protection Law (PIPL).

In contrast, decentralized solutions like Freemindtronic’s DataShielder offer fully offline, serverless encryption using NFC-enabled Android devices. With no central database or network dependency, these tools ensure true digital sovereignty—even on compromised platforms.

Microsoft Majorana 1: A Leap Toward Fault-Tolerant Qubits

On February 19, 2025, Microsoft unveiled Majorana 1, the world’s first topological qubit processor. Built on "topoconductors," it hosts Majorana zero modes (MZMs), promising inherently stable qubits resistant to noise.

While still experimental, Majorana 1 could scale to one million qubits per chip—potentially accelerating the path to fault-tolerant quantum computing. However, practical applications for cryptanalysis remain years away.

This breakthrough underscores that while progress is accelerating, the leap from lab prototypes to scalable, stable quantum computers is immense.

Action Plan: Preparing for the Quantum Future

Organizations must act now to avoid "harvest now, decrypt later" attacks—where adversaries store encrypted data today for future decryption once quantum computers mature.

Recommended steps:

  1. Upgrade RSA systems: Migrate from RSA-2048 to RSA-3072 or adopt PQC algorithms like Kyber or HQC.
  2. Strengthen AES-256: Use segmented key encryption to add defense-in-depth.
  3. Monitor NIST guidelines: Stay updated on PQC standardization timelines.
  4. Adopt hybrid encryption: Combine classical and post-quantum methods during transition.
  5. Consider offline solutions: Reduce attack surface with hardware-based, decentralized tools.

👉 Secure your data with next-generation encryption tools designed for the quantum era.

The Environmental Cost of Quantum Security

Operating large-scale quantum computers demands extreme cryogenic cooling near absolute zero—consuming vast amounts of energy and infrastructure. A fault-tolerant machine capable of breaking RSA-2048 would have a massive ecological footprint.

In contrast, offline encryption solutions like DataShielder require no servers or constant power, offering an energy-efficient, sustainable alternative that also resists centralized attacks.

As sustainability becomes a cybersecurity priority, low-power, decentralized models may prove both more secure and more responsible.

Final Outlook: Confidence in Current Encryption

While quantum computing will eventually reshape cryptography, RSA-2048 and AES-256 remain secure through at least 2035. The path to breaking them is long, requiring breakthroughs in qubit stability, error correction, and system scale.

In the meantime:

By combining proven symmetric encryption with innovative techniques and proactive migration planning, organizations can confidently defend against both current and emerging quantum threats—without panic or premature overhaul.