As our lives become increasingly more digital, new opportunities for hacking, impersonating, and thefts arise. Current encryption techniques are far from perfect and might soon prove obsolete at the hands of phenomena we do not fully understand.
Step into the unknown
From wristwatches to the supercomputers that run the Large Hadron Collider, all modern electronic devices use binary code, a two-symbol system consisting of 0s and 1s. The vision for new technology, however, is founded on quantum bits, widely known as qubits. Typically taking the form of photons and electrons, qubits are units of encoded quantum information. When harnessed, these subatomic particles will offer the raw processing power and security, the likes of which we’ve never experienced. But how? In order to dive deeper into the abstract, we must first take a look at the history of quantum physics.
A short history lesson on Quantum cryptography
The year was 1900, and physicist Max Planck had just presented his quantum theory to the German Physical Society. Planck proposed that energy, just like matter, was made up of individual units. 5 years later, Albert Einstein theorized that radiation could also be observed in a similar manner. This eventually led to the proposition in 1924 that particles can behave like waves and vice versa – known as Louis de Broglie’s principle of wave-particle duality.
No more than 3 years later, Werner Heisenberg came up with what became known as the uncertainty principle, where he proposed that a precise measurement of two complementary values was impossible, e.g. the position and momentum of a subatomic particle. Its notion defied the mathematical laws of nature, prompting one of Einstein’s most famous quotes,
“God does not play dice with the universe”.
What do a cat and a physicist have in common?
Over the years, the most powerful theoretical minds have contributed to our understanding of quantum theory – a process that is still ongoing. To this day, however, one of the most commonly taught interpretations of quantum mechanics is that of Niels Bohr and Werner Heisenberg, devised from 1925 to 1927. Known as the Copenhagen interpretation, their work claimed that no object in the universe can be assumed to have specific properties until it is measured. This concept became known as superposition.
Superposition is best explained through the paradox of Schrodinger’s Cat, named after physicist Erwin Schrodinger. To visualize the concept, imagine a cat in a sealed box with a vial of poison inside. We cannot know whether the animal is dead or alive until we open the box, so during this period of uncertainty, it is both dead and alive. By the same token, a qubit can exist in all possible states until it is measured.
Brothers in arms
Described by Einstein as “spooky action at a distance’, entanglement is a key phenomenon in quantum physics that signifies a shared, quantum state between a pair or group of qubits that makes each member of the pair or group inherently dependent on the others. In entanglement, a change in the state of one qubit immediately affects the others in a predictable way, for instance, in a pair of qubits with a measured total spin of zero, when one is known to have a clockwise spin, the other qubit must then have a relative counter-clockwise spin. What is interesting about entanglement is that so far no one has been able to explain exactly how or why it occurs. Spooky.
The practical application of quantum theory is a tantalizing prospect for technological breakthroughs, particularly in computing. Thanks to superposition, quantum computers can perform calculations for multiple possibilities simultaneously, as opposed to the one-at-a-time nature of digital machines. Furthermore, while conventional computers require additional bits to increase their processing capabilities, quantum computers use entangled qubits to provide unparalleled efficiency and raw power. The implications are colossal, spanning across fields and industries. From molecular modeling to forecasting in weather and finance, from machine learning in the automotive and medicine to particle physics, the future does look bright.
What’s the catch?
China is one of the main players in quantum research, having recently used its Micius satellite to successfully beam entangled pairs of photons to three optical telescopes over a record 1,203 kilometers, besting the previous record by almost 1,100 kilometers. Unfortunately, only one pair of photons out of the 6 million beamed each second survived the journey through our atmosphere. This is because even the smallest change in the environment, like a loud noise, can destroy quantum properties and result in computational errors – an occurrence known as decoherence.
To maintain their unique properties, qubits should be kept inside vacuum chambers at all times, having limited to no interaction with outside stimuli, which isn’t always possible. Decoherence is one of the biggest challenges to unlocking the full potential of quantum mechanics, but the prize for overcoming it is everything. The global leader in quantum computing is going to have an unthinkable advantage over the rest of the world. It’s a sprint, not a marathon.
What if I told you…
The world’s most popular encryption technique has many flaws that make it prone to interception and decryption. The effectiveness of RSA encryption relies on the difficulty of solving multi-factor problems involving large prime numbers. RSA keys, needed to access the encrypted message, are constantly at risk of factoring attacks, making them an easy target for quantum computers thanks to their multi-problem solving properties. The solution? Quantum networks. When operational, these will most likely be a specialized branch of the world wide web, offering secure data transfer, and more, to future you.
The knight in shining armour
But we do not have to wait 10 years for our data to be secure. Quantum cryptography is already here in the form of Quantum Key Distribution or QKD for short. QKD uses the principles of superposition to create an encryption system based on physics rather than, traditionally, mathematics. In order to relay information securely, the sender creates an encryption key using qubits, which are sent to the recipient. The sender and recipient then use key sifting to determine whether the operation was successful. Had the encoded qubit been measured by a third-party, the sender and recipient of the data would both be alerted by the collapse of the entire operation due to decoherence. The security of this encryption technology combined with the ability to sound an alarm when jeopardized is revolutionary for cybersecurity.
In a perfect world, the new ceiling in cybersecurity would make our planet an objectively better place. Quantum communication would provide freedom and security for those under suppressive governments. The safety of financial transactions would be at an all-time high thanks to quantum cryptography. We would be able to get in touch with our friends and family in total privacy via quantum networks. The subsequent developments in artificial intelligence would bring us closer to technological singularity, where miraculous advances would happen on an almost daily basis. Our grandchildren might even call it the “quantum age”. Sounds great, doesn’t it?