Quantum Computing in Cyber Security

Regardless of when quantum computers become commercially available, there is another reason to secure data against quantum threats now: the risk posed by malicious actors who are already collecting and storing data. These bad actors are stealing data with the intention of decrypting it once they obtain access to quantum computers. By that time, the data will already be compromised. To protect information, especially data that must remain secure in the long term, it is essential to implement quantum-safe key delivery now.

Quantum computers will be capable of solving problems that are too complex for classical computers to handle, including cracking the encryption algorithms that protect our data and the Internet’s infrastructure. Many of today’s encryption methods rely on mathematical formulas that would take current computers an impractically long time to decode. For instance, multiplying two large numbers is straightforward, but starting with the product and factoring it into its prime numbers is much more difficult. A quantum computer, however, can easily factor these numbers and break the encryption. Peter Shor introduced a quantum algorithm, known as Shor’s algorithm, which efficiently factors large numbers much faster than classical computers can. Since then, scientists have been focused on developing quantum computers that can factor increasingly larger numbers.

RSA encryption, a commonly used method for securing sensitive data online, relies on 2048-bit numbers. Experts estimate that breaking this encryption with a quantum computer would require a machine with approximately 70 million qubits. Given that the largest quantum computer today, IBM’s 53-qubit model, is far from this capability, it may take considerable time before such encryption is broken. However, with the rapid pace of quantum research, the development of such a powerful quantum computer within the next 3-5 years cannot be ruled out. For example, earlier this year, Google and the KTH Royal Institute of Technology in Sweden reportedly discovered a more efficient method for quantum computers to perform code-breaking calculations, significantly reducing the required resources. Their work, featured in the MIT Technology Review, showed that a 20 million-qubit computer could break a 2048-bit number in just 8 hours. This demonstration suggests that ongoing breakthroughs may accelerate the timeline for achieving this capability.

It’s important to understand that the primary concern regarding the quantum encryption threat isn't sensitive data that loses its relevance over time. The real danger lies in the exposure of information that must remain confidential for many years to come, such as data related to national security, banking, and privacy regulations. These are the critical secrets that urgently need to be safeguarded with quantum-resistant encryption, especially given the threat from malicious actors who are already stealing this data in anticipation of future quantum computers capable of breaking current encryption methods.

In recent years, researchers have been actively working to develop "quantum-safe" encryption. According to the American Scientist, the U.S. National Institute of Standards and Technology (NIST) is already assessing 69 potential new methods for what it terms "post-quantum cryptography (PQC)." While there are still many unanswered questions about quantum computing, scientists are diligently working to address them. However, one thing is clear: quantum computing will pose a significant threat to cyber security and our current encryption methods. To counter this threat, we need to rethink how we secure our data and start implementing changes now. The quantum threat should be approached like any other security vulnerability, with a defence-in-depth strategy that includes multiple layers of quantum-safe protection. Forward-thinking organisations recognise the need for crypto agility and are exploring diverse encryption solutions, such as those offered by Quantum Xchange, to make their systems quantum-safe today and quantum-ready for future threats.