Client portal

The credential is the account. The files sit in folders or tickets scoped to that account. NIST SP 800-53 AC-3 is the control: the server allows the approved identity and denies everyone else. A portal that works logged out is a public link with a logo.

The difference from an expiring link is lifetime and identity. A link dies on a clock and can be forwarded. A portal account survives until someone disables it, and a forward of the URL hits a login. The difference from managed file transfer is who acts. A portal waits for a person. An MFT job runs on a schedule with no one at the keyboard. Teams use both: the portal for the messy human exchanges, the job for the nightly file that must exist by 02:00.

An agency gives Northwind an account. In March the client uploads a 6 GB brief through a file request inside the portal. In April they download three cuts, each logged against the user, not against a one-time URL. When the contract ends, disabling the account stops the next login. It does not delete cuts already saved on the client's laptops. A vendor who instead emailed twelve separate links has no single switch, and the access log is a pile of anonymous URL hits. The portal costs a password reset flow and a session timeout. The links cost a trail of who-has-this guesses.

A portal is not a protocol. Under the session you still have HTTPS, object storage, and a size cap. The useful test is whether you can name the human, revoke them, and list their transfers without hoping they still have the email.