I have recently been looking at the technical documentation of @SignOfficial and noticed something that is rarely discussed: Trust Registry.
Most people talk about Sign by discussing how attestation is issued and how Schema is defined. But there is a more fundamental question: who is qualified to issue attestation?
In the architecture of Sign, the Trust Registry records all authorized issuers—public keys, approved Schema for use, and the entry point for revocation status queries. When the verifier receives an attestation, the first step is not to look at the content, but to check whether the issuer is in the Trust Registry. If not, it is directly rejected.
Thus, the Trust Registry is the root authority of the entire system. Whoever controls the registry controls the definition of "what is trustworthy."
In national deployments, this authority belongs to the sovereign institutions. The design of Sign divides roles into four layers: the sovereign party holds the root key to set policies, the operation party runs nodes but cannot change policies, the issuer must register to issue certificates, and the auditor can check but cannot modify. The four roles constrain each other.
What is interesting is that Sign plans to deploy in over 20 countries, each with its own independent Trust Registry. Issuers authorized in Sierra Leone are completely different from those in the UAE. But all attestations use the same Schema format, allowing for cross-border verification.
This creates a very clever structure—the proof format is universally applicable, while the issuance qualifications are autonomously managed by each country. It neither requires countries to give up data sovereignty nor guarantees that cross-border verification can run smoothly.
The consumption of $SIGN is bound to the lifecycle of the attestation. The more issuers registered in the Trust Registry, and the more frequent the issuance and verification, the greater the on-chain consumption. Compared to the total amount of attestations, I am more interested in the number of issuers in each country's Trust Registry—this number represents how many institutions have truly connected to Sign's trust network.