Group function based on signature and introduction mechanism

This post is about the idea of a more complete group mechanism. It intends to implement a modern group function similar to the Telegram group mechanism.
We noticed that the group function of Delta Chat is weak now. Especially for group management capabilities. The first improvement is the introduction of permissions and administrators. This requires relying on digital signatures. Email address based identification (https://github.com/deltachat/deltachat-core-rust/blob/master/spec.md Version: 0.33.0) is not acceptable due to significant security issues. For insecure email services, the sender address can be easily forged. We should address this at the Delta Chat level. A simple idea is to use a digital signature to confirm the identity of the creator administrator. There are many ways to implement it, such as holding an initial key by the creator. Creators can issue keys to administrators and notify other members to recognize their administrator status.
On this basis, there is a better way to invite others into the group. First of all, we cannot allow strangers to enter and leave the group at will, and digital signatures provide basic security guarantees. We can choose to invite through the administrator; or the administrator creates a public invitation code (limited or indefinite), and sends the invitation code to any online member in a certain format (which can be replaced by a robot) to complete the referral.
At the same time, we can introduce end-to-end group chat by publishing the public key.
The above is my vision for the group functionality, I don’t know how much autocrypt has implemented, or how much Delta Chat has implemented. At least in my brief use, the experience wasn’t perfect.
The above original text is in Chinese, translated by Google Translate.

reminds me of the “owned group” group type in New feature: Group Types
Autocrypt already provides crypto signatures for messages, so something like that could probably be implemented, though we still need to take care to ensure those groups will work with email contacts too, so it’s not as straightforward as it might seem.