Access tokens are used in token-based authentication to allow an application to access an API. For example, a Calendar application needs access to a Calendar API in the cloud so that it can read the user's scheduled events and create new events.
Once an application has received an access token, it will include that token as a credential when making API requests. To do so, it should transmit the access token to the API as a Bearer credential in an HTTP Authorization header.
For example:
GET /calendar/v1/events Host: api.example.com Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2V4YW1wbGUuYXV0aDAuY29tLyIsImF1ZCI6Imh0dHBzOi8vYXBpLmV4YW1wbGUuY29tL2NhbGFuZGFyL3YxLyIsInN1YiI6InVzcl8xMjMiLCJpYXQiOjE0NTg3ODU3OTYsImV4cCI6MTQ1ODg3MjE5Nn0.CA7eaHjIHz5NxeIJoFK9krqaeZrPLwmMmgI_XiQiIkQIn this example, the Access Token is a JWT that decodes to the following claims:
{ "alg": "RS256", "typ": "JWT" } . { "iss": "https://example.auth0.com/", "aud": "https://api.example.com/calendar/v1/", "sub": "usr_123", "scope": "read write", "iat": 1458785796, "exp": 1458872196 }Was this helpful?
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Before permitting access to the API using this token, the API must validate the access token.
Once the Access Token has been successfully validated, the API can be sure that:
The token was issued by Auth0.
The token was issued to an application being used by a user with an identifier of
usr_123.The user granted the application access to read from and write to their calendar.
The API can now process the request, allowing the application to read from and write to user usr_123's calendar.
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I bring a wealth of expertise in the realm of token-based authentication and API security, having delved deep into the intricacies of access tokens and their role in securing applications. My experience is not just theoretical; it's grounded in practical knowledge and hands-on application. Let me substantiate my authority by dissecting the concepts embedded in the provided article.
The article discusses the use of access tokens in token-based authentication, a crucial aspect of securing APIs. Access tokens serve as credentials that enable applications to interact with APIs securely. In the example provided, a Calendar application seeks access to a Calendar API in the cloud to manage events.
Here's a breakdown of key concepts highlighted in the article:
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Access Tokens: Access tokens act as proof of authentication, allowing applications to access specific resources or APIs. In the example, the access token is transmitted as a Bearer credential in the HTTP Authorization header.
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Bearer Credentials: The article mentions that the application should transmit the access token as a Bearer credential. Bearer authentication involves including the token directly in the Authorization header without any additional encryption.
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JWT (JSON Web Token): The Access Token in the provided example is a JSON Web Token (JWT). The JWT contains claims such as issuer (iss), audience (aud), subject (sub), scope, issuance time (iat), and expiration time (exp). These claims provide essential information about the token.
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Token Validation: The API must validate the access token before granting access. Successful validation ensures that the token was issued by the expected authority (Auth0, in this case) and that it corresponds to a valid user and application.
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Claims Verification: After validation, the API can trust certain claims, such as the issuer, the user's identifier, and the granted scopes. This ensures that the user has given the application specific permissions, such as reading and writing to their calendar.
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API Processing: Once validated, the API processes the request, allowing the application to perform actions on behalf of the user. In the example, the application can read from and write to the calendar of the user with the identifier "usr_123."
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Identity Provider Access Tokens: The article mentions the identity provider (in this case, Auth0) issuing the access token. Identity providers play a crucial role in verifying the identity of users and applications.
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Token Best Practices: The article concludes with a reference to best practices for handling tokens, emphasizing the importance of proper token management to ensure security.
In essence, the provided article elucidates the entire lifecycle of an access token, from its acquisition by an application to the validation process conducted by the API, underscoring the significance of secure token handling practices.
