The development of privacy technology seems promising—mixers, privacy coins, zero-knowledge proofs (ZK) are all available. But once cross-chain operations are involved, things get complicated.

Many people favor ZK-SNARKs, which excel at one thing: proving that you know a secret without revealing the secret itself. It sounds perfect. The problem is—when the scenario escalates to require continuous, high-complexity computations on encrypted data (such as verifying and transforming cross-chain asset states), ZK-SNARKs start to show limitations. These proof mechanisms are not inherently designed for such tasks at the foundational level.

In other words, there are still many gaps in privacy protection within cross-chain interactions.