A Chinese-built photonic machine known as Jiuzhang 4.0 executed a Gaussian boson-sampling calculation in 25.6 microseconds, a task researchers estimate would tie up the world’s most powerful supercomputers for 10^42 years. The demonstration, reported this week by New Scientist, marks one of the clearest laboratory assertions yet of “quantum advantage,” the point at which quantum processors outperform classical hardware on a defined problem. The leap is sharpening warnings that the arrival of large-scale quantum computers could upend today’s encryption. Analysts describe a “store now, decrypt later” risk, in which adversaries harvest encrypted data today with the expectation that future quantum machines will unlock it in seconds. Cryptocurrency advocates say Bitcoin and other blockchain-based assets are especially exposed. Industry and government planners are responding. Google and IBM both target commercial-scale systems by the end of the decade, while the U.S. Defense Department has launched a study to assess whether private-sector machines might deliver militarily relevant results by 2033. In parallel, the National Institute of Standards and Technology is finalising post-quantum cryptography standards meant to harden civilian and federal networks before that deadline. Oxford Ionics chief executive Chris Ballance expects quantum hardware to “outperform the largest supercomputers humanity will ever build,” a prospect that has moved editors at the Financial Times and other outlets to call for immediate investment in quantum-safe skills, algorithms and workforce training. Without a rapid shift to post-quantum defences, security specialists warn that the next wave of computing power could render much of today’s protected information transparent.