How can i update the document.key?

Can anyone help me?
I know that when I edited a document and save it, a history version is generated and a new document.key(Do not forget that every time the document is edited and saved, the document.key must be generated anew) value needs to be generated to update it. But there doesn’t seem to be an api to update this document.key. How should i update the document.key?

Document key generation is the task of the integrator and must be performed at the side of the document storage application. Document Server and its API have nothing to do with generating the keys.

Thank you very much