Tokens are at the center of API access control in the enterprise. Token management, the process through which the lifecycle of these tokens is governed, emerges as an important aspect of enterprise API management.
OAuth access tokens, for example, can have a lot of session information associated with them:
- Client ID
- Subscriber ID
- Grant type
- Associated refresh token
- A SAML assertion or other token the OAuth token was mapped from
- How often it’s been used, from where
While some of this information is created during OAuth handshakes, some of it continues to evolve throughout the lifespan of the token. Token management is used during handshakes to capture all relevant information pertaining to granting access to an API and it makes this information available to other relevant API management components at runtime.
During runtime API access, applications present OAuth access tokens issued during a handshake. The resource server component of your API management infrastructure, the Gateway controlling access to your APIs, consults the token management system to assess whether or not the token is still valid and to retrieve information associated with it, which is essential to deciding whether or not access should be granted. A valid token is not in itself sufficient. Does the scope associated with it grant access to the particular API being invoked? Does the identity (sometimes identities) associated with it also grant access to the particular resource requested? The token management system also updates the runtime token usage for later reporting and monitoring purposes.
The ability to consult live tokens is important not only to API providers but also to owners of applications to which they are assigned. A token management system must be able to deliver live token information, such as statistics, to external systems. An open API-based integration is necessary for maximum flexibility. For example, an application developer may access this information through an API developer portal, whereas an API publisher may get this information through a BI system or ops-type console. Feeding such information into a BI system also opens up the possibility of detecting potential threats from unusual token usage (frequency, location-based etc.) Monitoring and BI around tokens therefore relates to token revocation.
As mobile applications represent one of the main drivers of API consumption in the enterprise, the ability to easily revoke a token when, for example, a mobile device is lost or compromised is crucial to the enterprise. The challenge around providing token revocation for an enterprise API comes from the fact that it can be triggered from so many sources. Obviously, the API provider itself needs to be able to easily revoke any tokens if a suspicious usage is detected or if it is made aware of an application being compromised. Application providers may need the ability to revoke access from their side and – obviously – service subscribers need the ability to do so as well. The instruction to revoke a token may come from enterprise governance solutions, developer portals, subscriber portals etc.
Finally, the revocation information is essential at runtime. The resource server authorizing access to APIs needs to be aware of whether or not a token has been revoked.
The management of API access tokens is an essential component of enterprise API management. This token management must integrate with other key enterprise assets, ideally through open APIs. At the same time, token data must be protected and its access secured.