# What is a quantum computer?

A quantum computer is a machine that computes with qubits, which can hold a combination of 0 and 1 at the same time and can be linked so that their states depend on each other. For most tasks it is no faster than an ordinary computer. For a few problems with the right mathematical structure, a quantum algorithm makes the wrong answers cancel out and the right one stand out, and that gives an enormous speed-up. Today's machines have too few qubits and too many errors to threaten encryption. Breaking it would need a large, fault-tolerant machine that corrects its own errors, which nobody has built yet. For your company the practical point is narrow: such a machine would break the public-key cryptography that protects almost every connection you make, so the replacement has to be planned before it exists.

FAQ: [Post-quantum cryptography](https://netsenx.com/en/faq/pqc) · https://netsenx.com/en/faq/what-is-a-quantum-computer

## Read next

- https://netsenx.com/en/encrypted-traffic-analysis
- https://netsenx.com/en/features
- https://netsenx.com/en/blog/2026-10-27_harvest-now-decrypt-later

## Related questions

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