Does ACS based document download validates user permission on the URL launch?

Migrateduser

Hi All,

I have two questions regarding ACS url which are as below.

1. Once we have generated the ACS url for a specific document and launch it either it the browser or through program, does it validate the user permissions on launch of the url?
   Why I ask this question is, I assume that user's read permission is validated when we try to retrieve the ACS url.
   Once the url is generated, I guess, it doesn't validate the user permission on launch of the url. Why I ask this question, we would like to avoid a use case where ACS url is generated by a user who has access rights and then it is shared with some one else who is not authorized to see the document.

2. Is there a way to ensure that ACS url could be used only once and it expires or becomes unusable after its first usage?

Thanks in advance!