> Not sure why this is often labeled a blockchain-specific problem ... This means that online security itself would be threatened In fact, all forms of securit

> Not sure why this is often labeled a blockchain-specific problem ... This means that online security itself would be threatened In fact, all forms of security would be compromised. However, quantum cryptography is a thing. For example, China recently launched an actual, working, "ultra-secure" satellite communication system based on quantum crypto (https://www.scientificamerican.com/article/china-reaches-new-milestone-in-space-based-quantum-communications/ https://www.scientificamerican.com/article/china-reaches-new...). A fully realized quantum computer would be able to factor prime numbers in linear team using Shor's algorithm, and therefore would break the assumptions public-key cryptography at currently used key sizes. My rough understanding is that quantum cryptography is magic that provides an answer to this problem, so that if/when quantum computing is advanced enough to break all classical cryptography, there will also be a secure quantum based cryptographic capability to counter that threat. I don't know if there is work on applications of quantum cryptography to blockchain specifically. Seems like a very interesting question.