By Vivian Coyne
Though quantum computers are still primitive in testing, and far from a reality in anyone’s home, some people are already concerned about the possible security implications this new technology will present once it becomes readily available. Quantum computing promises faster speed and expanded storage, but may provide new challenges to users and security professionals in the future.
Quantum computers can be distinguished from classical computers by their most fundamental units of data. In classical computing, this unit is called a bit, and can take one of two values. In quantum computing, the fundamental unit is the qubit, which can be in either one state or the other or it can exist in a superposition of both states. Its properties are such that quantum computers can run multiple operations concurrently, rather than in sequence, which greatly speeds up the calculations it can make. However, the arrangement is very delicate: observation or contact from photons can be enough to destroy the setup. As a result, qubits must be entangled, allowing observation of one to yield information about the state of the other.
Development of quantum computers is still in the early stages. Microsoft, HP and IBM are working on them, as are defense companies like Lockheed Martin and universities such as the University of Waterloo and MIT. There are numerous ways to create qubits, so these parallel efforts approach the same problem in different ways as they work to develop a useful quantum computer. Degrees of optimism vary on how soon these computers will be available, though the more realistic tend to project that it will take several more years.
What will quantum computers mean for security? It turns out that having the speed to model complex systems like the weather, or predict the outcome of complex chemical reactions, or determine the behavior of proteins programmed by the human genome would also allow quantum computers to quickly perform tasks like factoring large numbers. Though this sounds mundane, the inability of classical computers to factor large numbers in a time frame that would be useful is what underlies the security of protocols like RSA, which is a common kind of encryption that allows secure transmission of information over the Internet. RSA alone is used in the operating systems of Apple and Microsoft products, as well as in numerous other devices. If quantum computing advances enough to compromise RSA, then this would have far-reaching consequences for personal and industry security.
The day remains far off from when we all have quantum computers—benign user and hacker alike. These computers will give those in business, finance and science the ability to perform calculations that are more complex much faster. They will even remove the simplifying assumptions currently necessary to manage the run time for elaborate programs. When it happens, it will likely also require a shift from one kind of previously secure encryption algorithm to other kinds that a quantum computer cannot compromise so easily. These may not sound like enormous changes, but we will not know the impact of this new technology until we can see what people do with it.