Somewhere right now, someone is storing encrypted traffic they can't read. They aren't cracking it. They're waiting for a machine that doesn't fully exist yet.

It's called "harvest now, decrypt later," and it's one reason quantum computing has moved from a physics-department curiosity to something developers need to understand.

I'll skip the "a qubit is 0 and 1 at the same time" explanation and tell you what's real, what's hype, and what you can do about it.

A short history: from a lecture to a hardware race

1981: Richard Feynman argues that simulating nature efficiently needs computers that obey quantum mechanics themselves.

1985: David Deutsch describes a universal quantum computer.

1994: Peter Shor publishes an algorithm that factors large numbers efficiently on a quantum computer. Suddenly RSA has a theoretical expiry date, and governments pay attention.

1996: Lov Grover shows a quadratic speedup for unstructured search.

2019: Google claims "quantum supremacy" with its Sycamore chip.…