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A mechanism to uniquely identify users and to provide protected access to the device.

The screenshot shows a sample login screen with a virtual keyboard to enter data.


The user needs to provide personalised credentials to log on to a system.


When users need to prove their identity, e.g., when logging on to their terminal for the first time or when changing shifts, a username/password combination is required.


Proper feedback for misspelled entries must be given when users provide their login details. The time required to log off and on should be minimised.


Provide a log on screen with two fields, username and password, and an on-screen keyboard to enable the user to type in username and password. This pattern is a composed structure consisting of the following basic patterns and elements:

Usability Impact

Error prevention

Safety Impact

Together with role management, this pattern provides an additional layer of security for the application. Competence and responsibility for the areas under control is clearly assigned.


This pattern has been used in several European railways projects.

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