What is two-factor-authentication?
If an account is protected by two-factor authentication (or two-step login), users can log in with a two-step process:
1. entering the username and password as usual;
2. and subsequently using the second factor. This is often an additional one-time password. This one-time password is usually generated by the online service concerned, and sent to the smartphone in a text message during the login process.
If even more additional authentication factors are used, this is referred to as multi-factor authentication.
There are also apps and tokens that can be used as a second authentication factor. More information on this is available at the Federal Office for Information Security
Many online services have started to provide the option of two-factor authentication. These two-steps accounts are very well protected against unauthorised access; it is no longer enough to just know the password. Especially in violent relationships, during and after break-ups and in other dangerous situations, this two-step login can provide additional protection. It is usually activated under the settings in the security and privacy menu.
By clicking on the following links, you will find information on how you can set up two-factor authentication with individual providers. Sometimes it is referred to with different names, such as two-step verification, 2FA or suchlike.