3⃣ Service Agent:
The service agent is also a cloud agent, and also provides services such as the issuance of some verifiable credentials (eg. diplomas from 3rd party institutions). It should also have a public and certified DID, and also needs to keep the secret key properly.
3.⃣ 服务代理：
服务代理也是一个云代理，还提供一些服务，例如颁发一些可验证的凭据（如第三方机构的文凭）。它还应该有一个公共的和经过认证的DID，并且还需要妥善保存密钥。