How would you share a temp access to a priv ftp without giving your credentials?

[kdlmm]

Hi, I was wondering how would you share a temporary access to a private ftp without giving your private credentials or creating a new ftp user (because, let's say, you don't have control over this) ?

I am thinking of developing a platform on which ftp's owners add there credential in a secure way, and create a temporary access to their private ftps accessible by a web UI. And let's imagine that ftp's owners could restrict access to specific folders/files of their ftp. Then, they can share a unique URL and let other users access the files without giving their credentials.

Is there already a solution like this?

Thanks!