Users subscribe to Vault Service on a trusted Hive Node to save personal application data. In principle, the data in the Vault is completely isolated from other DID users’ access, and only the Vault owner is allowed to save and access through DID. However, in practice, users not only need to save personal private data but also local public data. For example, in social applications like Twitter, users are allowed to designate their own blog content to share with their followers, and followers are also allowed to contribute their own comments or likes to blog content.