>2. Use online/cloud storage such as OneDrive, SharePoint or DropBox. Using DropBox as an example I could:
>- Set up one dropbox with a common user name/password for all users
>- put all file sets in the dropbox. Each one protected by ZipCrypto and unique passwords
>- Users download the file sets for their endpoints. If they download other users' file sets that's not a problem, they won't have those passwords
>- Delete the files from DropBox once all users have theirs
>
>The only real downside to something like this is the users need to be given two sets of credentials: one for DropBox and the other for their ZIP file(s).
>
2 sets of credentials is a benefit in my paranoid eyes. Having common dropbox makes gut twitch wrong way: no need to do that IMO... Subdirectory with different login for SFTP, WinSCP feels better than common dropbox.

key sent via SMS to force separate devices another option to add an ounce of security