Can the government really hide advanced technology?

Yes—governments can hide some advanced technology, especially specific military programs, prototypes, and capabilities, sometimes for years or even decades.

That said, it is much harder to hide a truly breakthrough, world-changing technology indefinitely. Once a technology depends on large supply chains, many workers, outside contractors, or repeated testing, the chances of leaks, detection, or independent discovery rise a lot.

A more accurate way to put it is:

• Easy to hide for a while: classified weapons, surveillance systems, stealth platforms, encryption methods, and other defense-related projects.
• Much harder to hide forever: something that would visibly change science, energy, computing, or transportation on a global scale.

So the short answer is: yes, governments can conceal advanced technology, but usually only specific programs—not an entire revolutionary scientific breakthrough forever.