I am currently working on a survey project and encountered a tricky problem: how to enable information providers to submit sensitive files completely anonymously and securely, while also ensuring that these files cannot be accessed by others before a specified time?

Traditional encryption methods have a fatal flaw—they always require someone to hold the decryption key. If that person is compromised, everything is ruined. We decided to try a different approach.

Using Walrus's Seal privacy protocol, we built a "decentralized dead letter box" system. The process is as follows: when uploading information, the file is first encrypted on the client side. Then comes the critical step—splitting the decryption key into dozens of parts using Shamir's secret sharing technique, and dispersing these parts across various verification nodes in the Walrus network.

Next, we write a smart contract to set the decryption rules. For example, in our case, the rule is: either after January 1, 2030, or upon obtaining joint signatures from five well-known journalists—if either condition is met, the verification nodes will release the key fragments.

What’s the brilliance of this scheme? Walrus's inherent censorship resistance guarantees that the files will never be deleted. Meanwhile, Seal's threshold encryption mechanism ensures that the files cannot be decrypted until the conditions are fulfilled. Honestly, even as a developer, I can't access the files prematurely if the time hasn't come or the required signatures aren't collected.

This is an example of enforcing trust through mathematics and code. For environments where information transfer carries high risks, this system offers a quite reliable protection.