Well, there's supposedly a much longer network in China: https://www.opengovasia.com/articles/8091-worlds-longest-unhackable-quantum-communications-link-opened

Well, there's supposedly a much longer network in China: https://www.opengovasia.com/articles/8091-worlds-longest-unhackable-quantum-communications-link-opened-between-beijing-and-shanghai https://www.opengovasia.com/articles/8091-worlds-longest-unh... The theory is sound and the technology is getting there. The question is really whether there's enough commercial interest. Joe Public doesn't care too much about this level of security, but governments, journalists, intelligence groups, and companies with a lot of intellectual property do. I predict that there will be some commercial uptake of this tech in 20 or so years time, but I don't think it'll be that exciting in terms of practical application. It's already possible to be confident that the pure algorithm is secure, i.e. communications can't be read without some sort of social engineering, backdoors or the like.