Quantum Computing, A Simplified Explanation.

Quantum computing is the study of a non-classical model of computation. Whereas a classical computer encodes data into fundamental units called bits, a quantum computer encodes data into qubits. The ability of these qubits to hold values that are not clearly defined is in contrast to classical computers that perform computations that never deviate from clearly defined values.

Another defining aspect of a quantum computer is its ability to link qubits together with quantum entanglement. Taken together, these quantum computer properties will enable computers to achieve a computational speed inaccessible by conventional (or classical) computers.

Classical computing (or binary computing) employs bits to store information, where a bit stores one piece of information containing a value that is either 1 or 0 depending on the state it is in.

In contrast, quantum computing uses quantum bits, or ‘qubits’. These qubits also have two states. Although the largest difference is that a qubit contains much more information than just a value of 1 or 0. Accordingly, the information contained in a qubit exists as values that relate to its position relative to the value 1 and 0.

Whereas 1 classical bit contains 1 individual piece of information (the value 1, for example), 1 qubit contains 2 individual pieces of information (that being the relative position to the value 1 and the relative position to the value 0).

When 2 classical bits exist, they can each store 1 value, thus resulting in one of four combined values: 00–01–10–11. In contrast, 2 qubits contain 4 pieces of information, where each piece of information is the relative position to one of the four values you can have with 2 classical bits.

The amount of information a classical bit system can store is equal to the number of bits that are being processed. In a qubits system, the amount of information it can store grows exponentially when more qubits are added. If we were to place this principle in a formula, it would look like this:

Consequently, 2 qubits can store 2² = 4 individual pieces of information, 3 qubits can hold 2³ = 8 individual pieces of information, 4 qubits can store 2⁴ = 16 individual pieces of information, and so on.

Moreover, a qubit not only stores more information than a classical bit, but before it is measured, it can also exist in every possible position (every superposition of 1 and 0) simultaneously. This is thanks to a particular ability of the subatomic particles employed by these systems.

If you imagine that a bit of information resembles a globe, a classical bit would be located on one of the poles of the globe. In contrast, a qubit could not only be found on any position on the globe, but it would be found in those locations simultaneously as well (before it is measured).

As a result, these qubits not only allow for much faster operations, they allow for much cheaper computing as well. Unfortunately, this technology cannot be applied to any conventional computer system operation. Instead, quantum bits only offer this advantage for specific operations in which the number of calculations required plays a far more significant role than the speed at which these calculations must happen.

As a result, quantum computing is only practical for specific computer operations and is by no means a replacement for classical computing. In some cases, quantum computing is actually slower than classical computing for certain processes. To fully benefit from qubits, an algorithm adjusted for quantum computing is required.

What Does Quantum-Resistant Mean?

The expression ‘quantum-proof’, ‘quantum-resistant’ or ‘quantum-ready’ refers to a process or algorithm in which quantum computing fails to prove advantageous in relation to classical computing.

In terms of encryption, these expressions refer to the fact that quantum computing will fail to break encryption within a reasonable time frame.

Thus, quantum-resistant describes any process or algorithm that prevents quantum computing from achieving an unfair advantage over classical computing. As such, a quantum-resistant blockchain can prevent quantum computing from rendering a highly secure encryption scheme as useless.

While several companies have created quantum computers, these computers are not only very expensive but impractical to use as well. In addition, they have yet to pose a serious threat to current encryption schemes or become widely available. Indeed, most if not all blockchain algorithms used today remain quantum-resistant given the current state of quantum computing.

Nonetheless, quantum computing remains in its early stages and is still being actively developed (and will be for years to come). This means that, in order to stay quantum-resistant, blockchain technology must stay at least one step ahead of quantum technology development.

Originally published at https://cloudsecuritytop.com on January 4, 2021.