Symptoms

I am using K2 Smart forms to upload document to SharePoint document library. I have to use SharePoint User credentials before uploading the document to Document Library. I am using Smart form Runtime URL to upload them. Is there any way to upload document to Document Library without logged in to SharePoint using SharePoint credentials??
 

Diagnoses

This is not possible as in order to carry out an upload document task the user must be recognized in some way by SharePoint.

An alternative could be that we utilize a workflow that uses the upload document wizard.

This would go through the K2 Service Account in order to upload the document as the K2 Service Account can impersonate other users.
 

Resolution

For this scenario since we are adding an item to SharePoint, yes we need the account that we are currently using to have rights on SharePoint if we are going to do an upload of a document.

Possible workaround for this is to just add a specific group in sharepoint that gives the user's the rights to upload a document and nothing higher. You could control these smartform users' sharepoint permissions via that group.

Another option could be that we instead utilize a workflow to upload this document to sharepoint. If we utilize the Upload Document wizard in a workflow, this would be doing the upload as the K2 Service account via that wizard.

Then we should just check what users are able to start this workflow and they would in essence not need to be logged into sharepoint. All rights would be controlled via who has participate and start rights on the upload document workflow.