Secure File Sharing

Web-based Secure File Sharing is done by uploading one or more files to a provider, who then generates a link/URL that you give to the recipient. You can send the link to the recipient however you prefer. The recipient can use any web browser and does not need an account with the service provider. They just click the link, see a web page with some information about the shared file(s) and then download the file(s) from this web page.

Both the upload and download of the shared files is encrypted with HTTPS, a very very common thing. The most important feature, however, is whether employees of the company offering the service can read your files. Even if employees can read the files you store at their service, it may be advertised as secure. It is not. The only secure file sharing is when the employees can not read your files. The technical term for this is end-to-end encryption and there is more about it on the Secure File Storage page.

On top of the basic end-to-end encryption, there are some add-on security features to look for.

Perhaps the most important add-on feature is password protection. A link that is shared by email, for example, is not secure as email itself is not secure. Without password protection, anyone who obtains the link to your shared files can download them, fully negating the end-to-end encryption. The hard part is sharing the password in a secure way.

Another add-on security feature is link expiration, where the link expires after a few days.

A more advanced security feature is an audit trail. Maybe you are sent an email any time the shared files are downloaded. Maybe there is a log you can check of every time the files are downloaded. Then too, you may be able to set a limit to the number of times the shared file(s) can be downloaded.

TRESORIT

Tresorit's main business is secure file storage, but they also have a free file sharing/sending service. You can upload/share 1 or more files up to a maximum of 5 gigabytes. Neither the sender nor the recipient needs a Tresorit account. All that Tresorit requires is an email address for the sender. They offer, but do not require, password protection for the sharing link/URL. With the free service, all sharing links/URLs expire in 7 days and shared files can not be downloaded more than 10 times. Tresorit emails the sender every time the shared file(s) are downloaded. The service is called Tresorit Send. I have used Tresorit Send and find the user interface very well done.

There are also two paid versions of Tresorit file sharing, one for Businesses and one for Enterprises. Among the added features are: Allowed viewers, Requiring an email to view shared files, Disabling download and printing and storage of 1 terabyte for shared files per user. They also have plug-ins for Outlook, Teams and Gmail.

PROTON

Proton Drive is mostly for secure file storage but it also does file sharing. Proton has both free and paid services. Even the free version of Proton Drive offers password protected file sharing with expiration dates for the shared links/URLs. I have used both Tresorit and Proton for file sharing and prefer the user interface of Tresorit.