Short answer
Authentication verifies who you are by confirming your identity, while authorization determines what you are allowed to do after your identity is established. The two are separate: one checks identity, the other decides permitted actions or access. 1 2
Authentication and authorization serve separate roles in security, with authentication establishing identity and authorization controlling access based on that identity.
On this page
At a glance
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| Question | Authentication | Authorization |
|---|---|---|
| Purpose | Proves user’s identity | Decides permitted actions |
| Typical Input | Password, token, or biometric | User attributes, roles, or policies |
| Order in Process | Occurs before access is granted | Occurs after identity is verified |
What each thing is
Authentication. Authentication is the process by which a user proves they possess and control authenticators bound to an account, thereby demonstrating they are the individual associated with that account. 1
Authorization. Authorization is a decision to grant access, typically automated by evaluating a subject’s attributes to determine what actions or resources are permitted. 2
Key differences
The key technical difference is that authentication focuses on proving the identity of a user or entity, while authorization is about determining what resources or actions that identified user is permitted to access or perform. 1 2
How to tell them apart
To recognize authentication, look for steps where you must prove your identity, such as entering a password or using a fingerprint. Authorization is tested when the system checks what you can do next, like accessing files or features. Some systems combine these steps, but they are conceptually distinct. 1 2
Where they overlap
Both authentication and authorization often use user attributes, such as account information, but for different purposes: authentication uses them to confirm identity, while authorization uses them to determine access rights. Systems may use the same data, but in different decision processes. 1 2
Edge cases
A tricky case arises in single sign-on systems, where authentication at one service can trigger authorization decisions across multiple services. While the two functions remain distinct, their boundaries may blur in complex federated environments. 1 2
Why the distinction exists
The separation exists because knowing who someone is does not automatically determine what they should be allowed to do. This distinction allows systems to enforce different levels of access and protect sensitive resources appropriately. 1 2
Common misconceptions
A common misconception is that logging in (authentication) automatically grants full access. In reality, after authentication, authorization still restricts users to only those actions or data they are permitted to access. 1 2
Examples
When you log into an email account, authentication verifies your identity with your password. Authorization then determines whether you can read, send, or delete messages, or access administrative settings, based on your account’s permissions. 1 2
Sources
Sources checked October 3, 2026.
- NIST Digital Identity Guidelines — Authentication glossary. Authentication terms.
- NIST CSRC — Authorization. Authorization definition.