Include a link to the django-rest-framework-api-key package

docs/api-guide/permissions.md

@@ -265,6 +265,10 @@ The [DRY Rest Permissions][dry-rest-permissions] package provides the ability to
 
 The [Django Rest Framework Roles][django-rest-framework-roles] package makes it easier to parameterize your API over multiple types of users.
 
+## Django Rest Framework API Key
+
+The [Django Rest Framework API Key][django-rest-framework-api-key] package allows you to ensure that every request made to the server requires an API key header. You can generate one from the django admin interface.
+
 [cite]: https://developer.apple.com/library/mac/#documentation/security/Conceptual/AuthenticationAndAuthorizationGuide/Authorization/Authorization.html
 [authentication]: authentication.md
 [throttling]: throttling.md
@@ -280,3 +284,4 @@ The [Django Rest Framework Roles][django-rest-framework-roles] package makes it
 [rest-condition]: https://github.com/caxap/rest_condition
 [dry-rest-permissions]: https://github.com/Helioscene/dry-rest-permissions
 [django-rest-framework-roles]: https://github.com/computer-lab/django-rest-framework-roles
+[django-rest-framework-api-key]: https://github.com/manosim/django-rest-framework-api-key