On the journey of privacy technology evolution, the popularity of ZK has not yet fully faded, and FHE (Fully Homomorphic Encryption) has quietly become the new favorite among developers. This technology sounds very cutting-edge, but in fact, it was proposed as early as 2009.

So why is FHE attracting attention again? The key lies in its capability: performing computations directly on encrypted data, which sounds a bit like magic. More importantly, it can solve a long-standing difficult problem—the seemingly irreconcilable contradiction between privacy protection and data usability.

On one side, data privacy needs to be protected; on the other, data needs to be leveraged for value. Balancing these has always been challenging. The emergence of FHE is like finding the equilibrium point, making both compatible possible. This also explains why this "old technology" has become a new trend today—technology has matured, and application scenarios are now clearer.