How Quantum Computing Could Break Today’s Encryption

Quantum computing is moving encryption from a distant research concern to a practical planning issue. Today’s internet security depends heavily on mathematical problems that conventional computers struggle to solve, including the difficulty of factoring very large numbers and calculating discrete logarithms. A sufficiently capable quantum machine could approach these problems in a fundamentally different way.

The change would affect far more than banking websites. Government records, medical information, cloud platforms, messaging services, business systems and connected devices all rely on cryptography. For Australians who use online services from Sydney, Melbourne, Brisbane or regional communities, the transition to quantum-resistant security will happen gradually, often behind the scenes.

Why Existing Encryption Is Vulnerable

Public-key systems such as RSA and elliptic-curve cryptography help websites, apps and organisations establish secure connections. They are used for digital signatures, identity verification, software updates and the exchange of encryption keys. Their security depends on calculations that would take classical computers an impractical amount of time to complete.

Quantum computers use quantum bits, or qubits, that can process certain mathematical structures in ways ordinary bits cannot. Shor’s algorithm is the major concern because, in theory, it could factor large numbers and solve discrete logarithm problems efficiently. If a quantum computer becomes powerful and reliable enough, it could expose private keys generated by many current public-key systems.

Symmetric encryption, such as AES, faces a different risk. Grover’s algorithm could reduce the effective security of some brute-force searches, although the threat is less dramatic than the one facing RSA and elliptic-curve methods. Using longer symmetric keys, careful implementation and strong key management can provide meaningful protection while organisations adopt new standards.

The Harvest Now, Decrypt Later Problem

Attackers do not necessarily need a quantum computer today. They can collect encrypted traffic and stored files now, then attempt to decrypt that information in the future. This strategy is known as “harvest now, decrypt later”. It matters most for data that must remain confidential for many years, such as health histories, legal documents, defence information, intellectual property and government archives.

An encrypted email or file may be safe against current equipment but still have long-term value to an attacker. Businesses should therefore assess the lifespan of their sensitive information rather than asking only whether a quantum machine exists. A company protecting customer data for ten or twenty years has a different risk profile from a service storing disposable session data.

This issue is relevant to everyday digital health habits as well. People who use telehealth, online prescriptions or patient portals should treat account security seriously, alongside practical wellbeing information such as daily diabetes prevention habits. Strong passwords, multi-factor authentication and cautious sharing remain useful protections while the cryptographic industry prepares for longer-term threats.

What Post-Quantum Cryptography Changes

Post-quantum cryptography, often shortened to PQC, is designed to resist attacks from both classical and quantum computers. Instead of relying on factoring or discrete logarithms, newer algorithms use mathematical structures believed to be difficult for quantum systems, including lattice-based, hash-based and code-based problems.

The National Institute of Standards and Technology has selected standardised algorithms for key establishment and digital signatures, giving technology vendors a foundation for migration. These systems are intended to work on conventional hardware, so organisations do not need to purchase a quantum computer to begin using quantum-resistant protection.

Migration will still be complicated. New algorithms can create larger keys, signatures or messages, which may affect mobile applications, low-bandwidth connections, smart devices and older enterprise systems. An Australian retailer processing payments through cloud infrastructure in Sydney may need to update application programming interfaces, certificates, hardware security modules and supplier integrations rather than simply switching one setting.

Australia’s Security And Regulatory Landscape

Australian organisations already operate under rules that require responsible handling of personal and sensitive information. The Privacy Act and the Australian Privacy Principles establish obligations around the management and protection of personal data, while sector-specific expectations can be stricter. Financial institutions, for example, must consider operational resilience and information security under regulatory frameworks such as APRA’s CPS 234.

The Australian Signals Directorate and the Australian Cyber Security Centre provide guidance on cyber risk, cryptography and secure systems. Federal agencies and critical infrastructure operators face especially strong incentives to plan early because their information may be targeted and must often remain protected for long periods. Canberra policy decisions can therefore influence banks, telecommunications providers, universities and technology suppliers across the country.

The local market adds practical pressures. Many Australian companies use global cloud platforms, outsourced software and international payment networks, meaning a cryptographic upgrade may depend on overseas vendors. Small businesses in Perth, Adelaide or regional New South Wales may also lack dedicated security teams, making asset inventories, supplier conversations and managed security services important parts of the transition.

Preparing Systems For A Quantum-Safe Future

The first step is discovering where public-key cryptography is used. Organisations should map certificates, VPNs, digital signatures, application programming interfaces, backups, identity systems, connected equipment and third-party services. An accurate inventory can reveal forgotten servers or devices that might remain in service long after their original support period.

Teams should then classify information by sensitivity and retention period. A migration plan can prioritise systems holding government data, financial records, health information and valuable intellectual property. It should also include crypto-agility: the ability to replace an algorithm, key type or certificate without rebuilding an entire application.

Useful actions for Australian organisations include:

• Create an inventory of cryptographic algorithms, keys, certificates and dependent vendors.
• Ask cloud, banking, software and telecommunications providers about their post-quantum roadmaps.
• Prioritise data that must remain confidential for many years.
• Test standardised quantum-resistant algorithms in non-critical environments.
• Upgrade identity, backup and device-management systems with crypto-agile designs.
• Train procurement, compliance and engineering teams to recognise long-term encryption risk.

Consumers have fewer technical decisions to make, but they can still use reputable platforms that support multi-factor authentication, install security updates and avoid reusing passwords. Readers can follow accessible technology and digital-security reporting through Ub24News technology coverage as standards and commercial products continue to develop.

Quantum computing is unlikely to unlock every encrypted message overnight. The larger risk is a slow transition in which organisations delay upgrades, retain obsolete systems and underestimate the value of archived data. Businesses, public agencies and technology providers should begin identifying vulnerable encryption now, test replacement methods and build quantum-resistant security into their next major technology refresh. Acting before a breakthrough arrives gives Australia’s digital economy more time to adapt safely.