Quantum computing creates qubits from particles, such as atoms or particles of light, or objects that mimic them, such as superconducting circuits instead of bits. Classical computers on the other hand employ a stream of electrical impulses in binary, meaning it uses 1 and 0 to encode information in bits.
Quantum computing will employ a one, a zero and a superposition of these to encode information in qubits. Superposition is when it in a complex combination of both one and a zero. Superposition is basically a system that has two different states at the same time that can be measured in multiple ways. For example, an electron has two possible quantum states: spin up and spin down. But since superposition principle says that if a quantum system can be in both states, then it can be placed in a linear superposition of these states.
Simply put, while bits can hold a zero or one, qubits can hold zero, one, or any proportion of both zero and one at the same time.
But the continuous nature of the state is not what makes quantum computing possible, it is the fact that multiple qubits can exhibit quantum entanglement. Entanglement is a nonlocal property that allows a set of qubits to express superpositions of different binary strings simultaneously.
While quantum computing sounds nice, there are variety of concerns that needs to be addressed. First we have decoherence with quantum computing, which means that even a slight disturbance can cause errors. Then we have other concerns like having correction solution for communication errors as well as security concerns.
While it’s easy to store information at 0 or 1, storing a quantum state is difficult and has to be shielded electromagnetically and temperature has to be cooled down to absolute zero. Qubits simply require precise physical conditions to function. However, the beauty of qubits is that if a hacker tries to observe them in transit, their super-fragile quantum state will “collapse” to either 1 or 0. This means a hacker can’t tamper with the qubits without leaving behind a telltale sign of the activity.
The biggest concern is how Quantum Computers pose an existential threat to our world. The Quantum Computing Cybersecurity Preparedness Act requires US Federal Agencies to upgrade to post-quantum encryption and to report their progress to Congress.
Because quantum computers will be able to break widely used public-key cryptographic schemes, the transition to new quantum resistant cryptographic algorithms has to be made. Quantum computing will put today’s cryptosystems, e-commerce, digital signatures, electronic identities, and such in jeopardy. This will be critical, even if rolling out new cryptographic systems might prove impossible for a certain systems with restricted accessibility like satellites.
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