'Quantum supremacy' and the threat it poses to data storage, digital economy

If data is the new oil, encryption is the engine that drives the digital economy. Everything from credit card transactions to health data stored on wearable devices is secured by cryptography. These complex algorithms, in turn, facilitate the safe use of the profusion of data generated every day.

The road to digitisation seems clear, but speedbumps abound. Last week, a team of researchers at Google claimed to have achieved ‘quantum supremacy,’ a major milestone in computer science.

“Our machine performed the target computation in 200 seconds and from measurements in our experiment we determined that it would take the world’s fastest supercomputer 10,000 years to produce a similar output,” the announcement said.


This feat was achieved using a 54-qubit processor, named “Sycamore” that was crafted using high-fidelity quantum logic gates. A quantum computer possesses the capability to solve problems that are beyond the ambit of modern supercomputers. However, it risks undoing extant encryption standards, bringing the engine of the digital economy to a sputtering halt.

By truncating computing time from 10,000 years to a little under four minutes, quantum computers pose an existential threat to industry standards in cryptography that were hitherto thought to be infallible in real-world conditions. Cybersecurity experts have reason to be worried.

End-to-end encryption, the one employed by messaging platforms like WhatsApp, are considered secure as it is difficult to decrypt the coded message sent from one user to another if it is intercepted by hackers. Even the most sophisticated computers in use would take thousands of years to divine the required cryptographic key if it tried all possible combinations – a practice known as brute force attack.

If quantum computers were to go mainstream, the use cases for cryptography would no longer be secure. The encryption used in professional network and in WiFi routers could be cracked in a matter of moments. Email and messaging services would be compromised. Banking transaction could be subverted, putting at risk the financial details of clients.

In its most basic form, an encryption algorithm is a math problem involving very large numbers. Encryption keys are hard to crack as they comprise of thousands of bits, making it difficult to determine the correct combination in real time. But the number of possibilities is finite, meaning that these algorithms are not foolproof if the computing power to process all combinations existed.

For instance, the 256 bit version of the Advanced Encryption Standard (AES) – the standard used by WhatsApp – would encode the data into cipher text that is 2256 long. It is probabilistically unlikely that one will have to skim through the whole list of possibilities before arriving at the right combination. Even if were possible to crack the code after trying out 50 per cent of the total permutations, the time taken would be inordinately long.

China’s Tianhe-2 (MilkyWay-2), which is widely regarded as one of the fastest supercomputers on the planet, would take millions of years to crack 256-bit AES encryption. This is longer than the universe’s life span, as predicted by astrophysicists. However, cryptography would be turned on its head, if instead, the universe were to unexpectedly dissolve into a cloud of dust in the time it took you to make coffee?

This could pose a big problem to the way information is exchanged on the internet. The death of the universe, in this example, is tantamount to the achievement of quantum supremacy. Traditional computers use the binary system, where each digit is encoded in 0s and 1s.

Quantum computers can take up an infinite number of values between 0 and 1 using qubits or quantum bits. This implies that a large number of calculations can be made at any given point in time as each qubit can process more information that its equivalent in a classical computer.

Google has taken the lead in the quantum race, but modern cryptography could be thrown into jeopardy if such computers were to fall into the hands of malevolent actors or rogue governments. Businesses will have to devise new ways to safeguard sensitive data, with protection extending to data transmitted across a network, and that stored locally on hard disks.

However, businesses have time to reorient their cybersecurity strategies given that quantum computing is still in its nascence. Quantum-proof encryption standards use algorithms that are inviolable to attack, regardless of the speed of the computer used. Most of these advanced techniques are lattice-based algorithms.

Unlike the classical encryption techniques in use today, lattice-based algorithms are impossible to crack owing to their organization in a virtual grid. The encryption key is hidden at the intersection point of a multidimensional lattice. Since the number of possibilities is infinite, quantum computers will be unable to leverage its advantage over classical computers as the number of permutations and the process of skimming through the range of possibilities is much more complex.

The cryptographic key can be determined only if the attacker knows their way through the lattice, which is theoretically impossible as there is no way to compute the path. This form of tricky encryption that could stump quantum computers is currently offered by companies like SAFEcrypto and Privitar. Despite the latest breakthrough, researchers at Google are yet orders of magnitude away from attaining the computer power to crack such algorithms.

To mount a credible threat, scientists will need to fit in more qubits to the existing architecture. The Google Sycamore system that attained quantum supremacy had a 54-qubit processor. Moreover, the absence of standard libraries for lattice algorithms adds to the complexity of integrating software with quantum hardware.

While lattice-based encryption services are costly, large companies might want to consider using it to secure critical data that has a long shelf life. Transactional data that is generated in bulk every day does not arguably require that level of encryption as its value to hackers depreciates over time. The threat to national security, however, is more worrisome.