Why Quantum Computing Could Challenge Today’s Internet Security?

Modern internet security is built on a long-held assumption: certain mathematical problems are so complex that solving them would take an impractically long time. Encryption systems such as RSA depend on this principle, relying on the difficulty of factoring extremely large numbers—something classical computers would take longer than the age of the universe to accomplish. This limitation has long safeguarded online banking, private communications and digital identities.

However, the emergence of quantum computing is beginning to challenge that foundation.

A Different Way of Computing

Unlike classical computers that process information using bits—either 0 or 1—quantum computers operate with qubits. These can exist in multiple states simultaneously through a phenomenon known as superposition. Another key feature, entanglement, allows qubits to be interconnected in ways that enable quantum systems to solve certain problems far more efficiently than traditional machines.

A Direct Threat to Encryption

This shift becomes particularly significant in the context of encryption. One of the most discussed quantum algorithms, Shor’s Algorithm, has the potential to factor large numbers exponentially faster than classical methods. If realised at scale, it could render current encryption systems vulnerable.

RSA encryption, which underpins much of today’s internet security—from secure websites to financial transactions—could, in theory, be broken by a sufficiently powerful quantum computer running this algorithm.

Technology Still in Early Stages

Despite the concerns, experts caution that the threat is not immediate. Current quantum computers remain limited by instability, noise and the absence of effective error correction. Most existing systems operate with a relatively small number of qubits, and maintaining their coherence long enough to perform complex calculations remains a major technical hurdle.

Breaking modern encryption would require fault-tolerant quantum machines with thousands, if not millions, of stable qubits—technology that is still under development.

Growing Concern: ‘Harvest Now, Decrypt Later’

Even so, cybersecurity experts warn of a long-term risk known as “harvest now, decrypt later”. In this scenario, encrypted data intercepted today could be stored and decrypted in the future, once quantum computing capabilities advance.

This poses particular risks for sensitive information that must remain secure for decades, including government communications, financial records and personal data.

Preparing for a Post-Quantum Era

In response, researchers and organisations worldwide are developing quantum-resistant encryption methods, commonly referred to as post-quantum cryptography. These systems are designed to withstand attacks from both classical and quantum computers.

Efforts led by institutions such as the National Institute of Standards and Technology are already underway to standardise new cryptographic algorithms for future use.

A Complex Transition Ahead

Transitioning to quantum-safe systems, however, will not be straightforward. Updating global digital infrastructure requires coordination across governments, industries and technology providers. Many existing systems were not designed with quantum threats in mind, making adaptation both urgent and technically demanding.

A Matter of Time

While quantum computing is still evolving, its potential impact on cybersecurity is reshaping global planning. Experts say the question is no longer whether current encryption could be broken, but when.

As research progresses, the foundations of digital security are being re-examined—signalling a shift that could redefine how the internet is protected in the years to come.