Devices and methods provide for enabling a user to use a single user authentication device such as smart-card reader, such that the user is capable of securely interfacing with two or more isolated computers and enabling the user to authenticate and remain authenticated at multiple computers at the same time. Once the user removes the smart-card from the smart-card reader, the authentication session on all coupled computers is terminated at once. The user authentication device comprises: an authentication module connected via a channel selection switch to one of a plurality of channels, each interfacing with a respective coupled computer.