If you only prove your age, your wallet address does not actively reveal your identity. But "does not actively reveal" is not the same as "totally anonymous"—whether you can be traced depends on what you do on-chain and how much information the tracker already has.
Selective Disclosure: Verifiers Only See What You Choose to Show
zkKYC, World ID and similar tools are built on "Selective Disclosure." It lets you show only the information you are willing to share, while everything else stays hidden.
For example, if a service only requires that you are "over 18," you generate a zero-knowledge proof (ZKP) and send it. The verifier receives only a "yes/no" answer, plus an encrypted signature that proves the answer is valid. Your name, birthday, address and other details are never seen by the verifier.
StarkWare's Private KYC solution works this way: after a user scans their passport, the data is encrypted and stored in their own wallet. When verification is needed, they submit only a zero-knowledge proof that "I meet a certain condition," not "who I am." Their principle is: "Verification should confirm a specific fact, not expose a full document."
Wallet Address: Your On-Chain "Fingerprint"
The problem is that although the verifier cannot see your name, it can see the wallet address you use to submit the proof. And every transaction from that wallet address is publicly recorded on-chain.
If this address meets any of the following conditions:
- It has completed KYC on an exchange
- It has transferred funds with other addresses whose identities are known
- It has been tagged by on-chain analysis tools
Then trackers may be able to link "an address" to "a person" through these public records. A wallet address is not a name, but it is an on-chain "fingerprint" you leave behind.
World ID's design includes a concept called "anonymous proof." When users verify, the system creates a credential tied to a specific service, rather than directly exposing the World ID itself. But this model also relies on an on-chain registry—verifiers check on-chain records to confirm the credential is valid, and this process still leaves traces of the wallet address.
