User (computing)

Accounts, names and identifiers

To use protected services a person usually holds a user account and a visible name: a username, screen name, handle, or nick. For access the account commonly uses a secret such as a password or other credential. When authentication succeeds the system grants an identity token; many operating systems then map that identity to an internal numeric identifier (for example a UID) so the kernel or service refers to the session by an integer rather than the human-readable name. This separation helps with efficient permission checks and auditing.

Authentication vs. authorization

Authentication is the process of verifying who someone or something is (for example by password, biometric, or cryptographic key). Authorization is the separate process of deciding what that authenticated identity is allowed to do. An authenticated user may still be denied particular actions until the system grants the required privileges. The operating system and application software collaborate to enforce these rules.

Common types of users

• End users: people who use applications for productivity, communication or entertainment.
• Power users: experienced users who customize or extend system behavior.
• Administrators (admins, root): accounts with broad privileges to configure systems and manage other users.
• Service or system accounts: non-human identities used by daemons, scheduled tasks or integrations.
• Guest or temporary accounts: limited, short-lived access for visitors or automated tests.

History and context

The notion of a user emerged as computing moved from single-user machines to time-sharing systems in the 1960s and 1970s, when multiple people needed concurrent access to a central machine. Over time, the concept grew to include remote network services, web applications, and API clients, each of which treats "users" as principals with assigned rights and profiles.

Uses, importance and best practices

Users enable personalization, resource accounting, access control and audit trails. Responsible management of user accounts is central to security: common best practices include using strong, unique credentials, enabling multi-factor authentication, applying the principle of least privilege, separating administrative and daily accounts, and regularly reviewing permissions. Service accounts should have minimal rights and expire or rotate credentials when possible.

Distinctions and notable facts

In technical contexts it is useful to distinguish between a "user" (the human or agent), an "account" (the set of credentials and metadata), and a "principal" (the authenticated identity recognized by a system). Modern identity systems also support federated users, single sign-on, and role-based models that group permissions into manageable roles rather than granting rights directly to each account.

For further reading about how users are represented and managed in different environments, see platform documentation and standards on authentication and access control (computer), (network), and (software) design, or consult specific operating system guides (operating system). Technical references often illustrate how numeric identifiers such as a user (integer) map to visible names and how passwords and other secrets (password) are protected in transit and storage.