From Robert Peck, York, UK
The quantum internet may not solve all our security problems (29 May, p 36). While any technology that reduces the ability of states and criminals to conduct surveillance and sabotage is to be welcomed, quantum communications are unlikely to be enough without a lot more technical work.
Another possibility is post-quantum cryptography. This still uses mathematics rather than photons, much like current cryptography, but aims to be resilient to the likes of encryption-busting methods in the quantum computer era, such as Shor’s algorithm.
This has the advantage that it can easily work for stored data and over wireless radio links, neither of which have yet been proposed for quantum cryptography, which relies on real-time optical-fibre connections or precisely aimed laser link connections.
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