Login (information technology)

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Registration on a website

As login or log-in (from English : (to) log in = "log in", "register" → "[user] login", also: sign-in / sign-on , log-on etc.) the process of logging into a computer system ( logging in ). The purpose of the process is usually to inform the computer system that a session is now beginning and that the user would like to be linked to a user account that grants him certain access rights. The login is used to identify and authenticate the user .


The Log into a computer system is done by providing a user name and either a secure password (or password), possession of a unique Identifzierungsgegenstands or even a biometric characteristic can be queried. After authentication has taken place , the user receives personalized access to the computer system, with the user profile specifying which data and applications he is specifically authorized to access ( authorization ). If you are logging into a computer network , you are logged in via a network service . With the login , a so-called session begins , which is ended by a logout . If a user does not yet have a user account for the computer system in question, he must first register with the computer system in order to create his own account.


Security and privacy issues

To protect username and password from unauthorized access, logging into a computer system over a network should always be encrypted . In addition, the access data to the user account can potentially be intercepted by keyloggers and phishing during the login process. Two-factor authentication is therefore often required, particularly for critical applications such as online banking .

"Sign in with"

Several large cloud providers such as B. Amazon, Apple, Facebook or Google offer a "Sign in with" service. With the help of this service, a user can also register and log in to various other Internet applications using his access data for the cloud provider. This service is also known as single sign-on . The user account with the cloud provider thus becomes the central "Internet identity" that provides access to various online services. The service is based e.g. B. on the OAuth protocol. The required personal data is transmitted to the internet application provider (the third party provider) by the cloud provider during the login. The third-party provider is usually authorized to access the name, e-mail address and profile picture as part of the "Log in with" service. Google recommends that you only grant this permission if you trust the website or app. “Log in with” saves the user from having to manage numerous passwords, and the cloud provider is informed about their own behavior. If the access data to the cloud provider should fall into the wrong hands, the attacker will also have access to all linked services. Facebook also transmits the public profile and the friends list; further data can be transmitted if the user does not explicitly exclude this. Apple allows the user to hide their personal email address from the third party.

Computer-to-computer communication

In addition to the form of the interactive login , the term login is also used in relation to the registration of a computer in a network via DHCP , SMB , RADIUS or another protocol .


In quiz programs , the term log in is also used as “mandatory input for quiz answers into the computer”.

See also

Web links

Commons : Login  - Collection of pictures, videos and audio files
Wiktionary: log in  - explanations of meanings, word origins, synonyms, translations
Wiktionary: Log-in  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. Authentication, authentication and authorization . By Agnieszka Czernik, datenschutzbeauftragter-info.de, Intersoft Consulting Services AG, June 24, 2016
  2. a b "Facebook Login" - What does data protection say about single sign-on? By Cornelia Brinks, datenschutz-notizen.de, DSN Holding GmbH, Bremen, March 8, 2015
  3. ↑ Use a Google account to log into other websites or apps . Google support
  4. Login via Facebook Connect - data protection-compliant use possible . datenschutzbeauftragter-info.de, August 20, 2014
  5. "Sign in with Apple" - This is how Apple's private log-in service works . t-online.de October 14, 2019
  6. Log-in service: check your Facebook login regularly . By Alexander Kuch, teltarif.de Onlineverlag GmbH, Berlin, December 8, 2019
  7. "Log in with Apple": Apple's login service is mandatory . By Leo Becker, heise online, June 4, 2019
  8. Use " Sign in with Apple" . Apple support