What are the characters on this seal?

[![enter image description here](https://i.stack.imgur.com/eg1wW.jpg)](https://i.stack.imgur.com/eg1wW.jpg)

Flipped image for easier reading:

[![enter image description here](https://i.stack.imgur.com/g9hqx.jpg)](https://i.stack.imgur.com/g9hqx.jpg)