THE MICIUS EXPERIMENT
The Chinese satellite Micius, launched in August 2016, is the first quantum communications satellite specifically designed to deliver ultrasecure communications by creating and transmitting uncrackable (cryptographic) keys from a remote location. The idea of wedding quantum computing and satellites to provide encryption security that’s flawless in its ability to reveal and thwart hackers could be historic.
The Micius scientists are collaborating with the Austrian Academy of Sciences, which is set up to receive the quantum signals from the satellite. Writing for forbes.com, Saadia M. Pekkanen reported, “China aims to achieve the Asia-Europe intercontinental quantum key distribution by 2020, and build a quantum communication network by 2030.”
Quantum computers are in their infancy and won’t be replacing “classical computers” any time soon. But the differences between “classical” (binary) computers and quantum computers are stark.
Perhaps the best approach to understanding quantum computing would be to start with the caveat that there is no science more counterintuitive than quantum mechanics, the branch of physics that covers these computers.
Today’s computers are built on the rules of human logic and the operations of electrical currents or photon streams managed by microchips. The information for the calculations is built on bits, 0s and 1s, which act like mechanical switches controlling the flow as sets of instructions (programs) are carried out. As you might reasonably expect, a bit can only be in one state to work—it’s a 1 or a 0, on or off.
In quantum computing, physical laws are replaced with the rules of quantum mechanics—rules that can appear impossible to creatures who heavily rely on their senses. With quantum computers, the basic bits of information aren’t binary bits but qubits, 0s and 1s that can be in one state or the other, or they can be in both states at the same time, or they can represent any point in the continuum between 0 and 1. The ability to represent both states, 0 and 1, simultaneously is called superposition. This quality of simultaneity gives quantum computers a built-in parallelism that can enable them to work on simultaneous computations.
These qubits, with their complex states, are subject to another odd quantum characteristic called entanglement. Wikipedia defines quantum entanglement as “a physical phenomenon that occurs when pairs or groups of particles are generated or interact in ways such that the quantum state of each particle cannot be described independently of the others, even when the particles are separated by a large distance.” You can’t read entangled qubits without their pairings or groupings. And as qubits become more entangled, the complexity of their information soars, as do the potential computations.
We aren’t done. Like other quantum states, qubits are fragile. This creates the odd phenomenon that any attempt to measure or observe qubits will reduce them to the classic state of simply 0s or 1s. This does present a significant security feature described in the No Cloning Theorem (by William Wootters, Wojciech Zurek, and Dennis Dieks). If anyone, like hackers or enemies, tries to read or steal (copy) the information in a quantum stream, it not only collapses, losing superposition and entanglement, it effectively notifies everyone that tampering has occurred—a super quantum alarm system, so to speak.
What the power of quantum computing could do to, and for, encryption is revolutionary. Johns Hopkins cryptography researcher Matt Green told PC Magazine, “Pretty much all of the public key encryption algorithms we use today are vulnerable to quantum cryptanalysis…Normally [it] would take millions and millions of years for standard classical computers to break, but if we are able to build a quantum computer, we know algorithms we can run on it that would break these cryptographic algorithms in a few minutes or a few seconds. These are the algorithms we use to encrypt pretty much everything that goes over the Internet.”
As to how important quantum computers might be, Vivek Wadhwa offered the following in The Washington Post: “[They] will enable better weather forecasting, financial analysis, logistical planning…and will compromise every bank record, private communication, and password on every [classical] computer in the world.”