Quantum supremacy and cyber risks: threats and strategies for resilient Cyber Security

Quantum Technologies (QT) are on the verge of redefining the technological landscape, promising significant advances in areas such as metrology, AI, or materials science. However, as with any transformative technology, quantum computing also entails considerable risks, particularly in the realm of Cyber Security.

The ability of quantum systems to perform calculations at unprecedented speeds poses a threat to the cryptographic foundations that underpin today’s digital world. The convergence of opportunities and risks in quantum computing calls for attention from governments, businesses, and Cyber Security professionals alike.

The new era of computing: what makes quantum computing different?

It introduces a paradigm shift in computational power. Unlike traditional computers, which process data in binary bits (0s and 1s), quantum computers leverage 'qubits', a term coined by theoretical physicist Benjamin Schumacher, that can exist in multiple states simultaneously thanks to the principles of superposition and entanglement.

This capability enables quantum systems to solve complex problems exponentially faster than traditional computers, revolutionizing optimization, drug discovery, and AI.

Cryptographic risks: an existential threat to digital security

However, this same power creates an existential cyber threat to today’s encryption standards. Public-key cryptography, which underpins secure communications and digital transactions, is vulnerable to quantum cyberattacks capable of decrypting information that would take traditional computers millennia to crack.

While quantum computing represents revolutionary advances, it forces the world to rethink Cyber Security strategies.

Peter Shor’s quantum algorithm, developed in 1994, can factor large prime numbers, a process traditional computers struggle with. It reveals the potential to directly undermine RSA encryption, whose security is based on the difficulty of prime factorization. Similarly, elliptic curve cryptography (ECC), used in secure communications and digital signatures, is also at risk.

The HDNL cyber threat refers to the possibility that cybercriminals may steal encrypted data today with the intent to decrypt it in the future, once quantum computers have reached the necessary capabilities.

This means that sensitive financial, governmental, and personal information could be vulnerable in just a few years, rendering today’s security measures insufficient against future cyber threats.

Global response: toward post-quantum cryptography

In response to quantum cyber threats, NIST is working on the development of post-quantum cryptographic (PQC) algorithms that are resistant to quantum cyberattacks. NIST is finalizing new encryption standards to replace RSA and ECC.

However, the transition to encryption robust against quantum cyberattacks poses major challenges. Organizations must reassess their current security infrastructure, update protocols, and ensure backward compatibility—all while maintaining operational integrity.

This could be particularly complex and challenging for sectors that rely on integrated and interconnected systems, such as banking and telecommunications, as well as in the OT environment, where hardware and software updates are costly and complicated.

Quantum computing represents revolutionary advances, but it forces the world to rethink Cyber Security strategies.

New attack vectors: quantum AI and advanced signal processing

By breaking encryption, these technologies introduce new risks. Cybercriminals could exploit machine learning driven by quantum intelligence to develop more sophisticated cyberattacks—automating vulnerability discovery and optimizing attack vectors.

Quantum computing could also be applied in advanced signal processing, allowing malicious actors to breach security measures in encrypted communications across data, voice, video, and satellite.

There is a convergence with AI that accelerates these risks, enabling the identification and exploitation of Cyber Security weaknesses more efficiently than ever before.

Quantum supremacy and digital geostrategy

Quantum technologies are poised to become the cornerstone of cyber warfare and intelligence operations. Several governments are investing in these technologies and recognizing their potential to enhance cryptographic capabilities and disrupt adversary communications.

Quantum supremacy is becoming a key goal for state actors.

The strategic implications are vast, as nations achieving advanced quantum decryption capabilities could jeopardize intelligence, disrupt financial systems, and undermine global stability. It’s a high-stakes race for quantum dominance in terms of national security and geopolitical power.

Advanced solutions, persistent challenges

Quantum Key Distribution (QKD) is often presented as an advanced solution for communication security in the quantum era. This method leverages the principles of quantum mechanics to establish encryption keys that, according to the no-cloning theorem, are theoretically immune to tampering.

While it enhances security, it is not a universal solution. It requires specialized infrastructure, is vulnerable to side-channel attacks, and does not protect data at rest or previously encrypted data exposed through HDNL strategies.

■ QKD is an essential tool in quantum security and it must be complemented by strong, robust encryption standards.

Critical infrastructure and economic consequences

Some cyber threats could disrupt processes, invalidate signatures, and compromise systems. Meanwhile, critical infrastructure, including energy and telecom networks, faces the risk of quantum cyberattacks that could render essential services inoperable.

The question is not whether quantum technology will disrupt Cyber Security, but when—and how prepared we will be.

Global supply chains, which depend on secure data exchange, could be compromised by quantum decryption capabilities. But the economic consequences of failing to adopt quantum-safe security could be catastrophic, leading to financial instability, espionage, and national security vulnerabilities.

Recommendations: anticipating with strategy and talent

Organizations should take proactive steps to prepare for the post-quantum era:

• Conduct quantum cyber risk assessments.
• Adopt hybrid encryption models.
• Invest in training and specialized talent.

■ Developing a Cyber Security strategy today that is resilient to quantum technologies is essential to avoid improvising solutions when decryption capabilities become widespread.

Conclusion

It’s important to act now to avoid being caught off guard. Emerging technologies like lattice-based cryptography, quantum random number generators, and AI-driven Cyber Security will shape the future of quantum security.

Organizations must keep their security posture agile and constantly updated to adapt to these advancements.

This represents both an unprecedented technological revolution and an imminent security crisis. The question is not whether quantum technology will disrupt Cyber Security, but when and how prepared we will be.

Get our handbook on protecting data from the quantum threat

At Telefónica Tech we advocate for a cryptoagility-based strategy, enabling systems to adapt to new threats without disrupting operations.

■ We invite all organisations to access our complimentary handbook Strategic preparation for Post-Quantum Cryptography and take the first step towards a resilient cryptographic infrastructure ready for the quantum era.