2-Factor Authentication (2FA) Using a Desktop or Notebook Client

One of the most important aspects of 2-factor authentication is that the 2^nd factor is displayed on a separate device.
However, as it is now becoming more common to use the smartphone or tablet (running the 2^nd factor app) as a full-fledged computer, this is already being softened there - analogously, it is also possible to use programs on the computer (desktop/notebook) that calculate the code for the 2^nd factor.

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